Cognitive Mileage

Bright Splotches Under Macbook Screen From Water Spill

Posted on: May 1, 2008

So my girlfriend’s daughter accidently spills water all over my Macbook screen leaving huge bright white splotches in the lower right and left corners of my screen. I freak out and take my MB to an Apple technician and he tells me it will be $750 to replace the screen but that I can probably just evaporate the water myself by running an intensive process that heats up my MB. Obviously, I opt for the latter.

The following Python program did the job.

i = 0
while True:
    i = i + 1

It got my CPU A up to a consistent ~80c with the fans obviously kicking on high. I put some pillows behind the screen to increase the heat.

I’ve been running it for about 3 hours now and the splotches are almost cleared up. It will probably take 4-5 hours total to complete the evaporation. But it beats paying $750 for a replacement..

There seems to be no permanent damage to the screen.

Well, it has been about 15 hours total now of drying, some with the program on, most with it off and the splotches are almost all gone. All that is left is a little pea-sized dot for the right splotch. I’ve no reason to think it won’t disappear by the end of the day.

24 hours later: screen is as good as new. You wouldn’t be able to tell the difference if you tried.


84 Responses to "Bright Splotches Under Macbook Screen From Water Spill"

Can’t thank you enough for posting this– I just switched from my old MBP to an MB last week, and while juggling some papers last night, spilled a large glass of water and got splotch across 1/4 of my screen. 12 hours later, it’s only an inch by 1/4 inch, so I’m hopeful it’ll all dry up.

I’m not a coder, and my devs were offline last night, so I don’t think I got the python script running right. My alternative was to:

– Handbrake a long movie on slowest settings.
– Run Itunes, a Quicktime movie and play the DVD being handbraked.
– Use SMCFan to crank the fan to max.

Kept things hot and fanning all night.

Glad to hear it helped morren!

Thank you so much for this, I fixed my screen!

I am a college student and I was walking to class on campus and before you know it, it starts pouring down heavy rain. Unfortunately, water leaked into my backpack and into my MacBook.

After leaving it off for a couple days and letting everything dry out, I turned on my mac and by the grace of God, it still worked after the monsoon.

Unfortunately though, there was this big cloud in the middle of my screen. Thankfully I did some googling and found your blog after Apple said they will NOT cover the cost of an LCD. I downloaded SMCFan and cranked the fans to the max and ran several applications just to make sure the computer was workign hard. 48 hours later, the spots are nearly gone.

Thanks for posting this!

seems work… will try it now… update later

I had this happen to me, but I don’t know how to run a Python script or Handbrake a DVD. Any advice?

Thank you so much for this post, worked wonders on my screen 🙂

I’m in the middle of the process and I’m not seeing any change.
I can only get the temp to a little above 50 though…

thanks a lot, and if you dont know how to run a python script or hanadbrake a DVD ?? you can type this into terminal and it does the same : yes > /dev/null

run it twice until most of it is gone (w/ 2 terminal windows) and then only use 1 🙂 hope it helps!! thanks u saved me a lot of money!

Thank you!!! This post saved my screen!

Glad to hear it guys!

hi Today i spelt some water onto my macbook….(its a macbook and its white idk if thats the pro or not.) I am COMPLETELY mac-illiterate…i have these shiny spot…here is a link to the picture

so every thing you guys just said…i have no clue what it means and i rlly want to get this fixed! i downloaded that smcfan thing and its currently at 136F and its doing nothing…… help?

Hi, really not too sure how this ‘Python’
works, where i get it or how i do it.
If you could teach me in steps it will be
MUCH appreciated!!!


wait, will handbraking a dvd definetley
clear up some of the water?
cause if i handbrake a couple of long
movies, it should make a difference right?


Very Interesting post! Thank you for such interesting resource!
PS: Sorry for my bad english, I’v just started to learn this language 😉
See you!
Your, Raiul Baztepo

Hi ! 😉
I am Piter Kokoniz. Just want to tell, that I like your blog very much!
And want to ask you: is this blog your hobby?
Sorry for my bad english:)
Your Piter Kokoniz, from Latvia

I’m having trouble figuring out how to run this python program. What do I type in?

Thanks dude!
This is a cool solution.
I don’t fully understand what the script really does but as soon as I ran it the fan kicked in. My laptop is slowly heating up now. Hope it works!

Hi did you just put the screen up at a 90 degree angle? like upright or tilted? doe sit matter? thank you so much.

Last night some ass spilled a sugary coffee on my white macbook… I’d like to try to fix it myself before making him pay for the new part.

There is a small and bright blotch on the bottom right and a larger on in the middle.

I will try this evaporation method but I wonder if the sugar will stay.

Is the glossy party of the screen a layer over the LCD? If so, Can i just take off this layer, clean under it and put it back on?

It’s a long-shot but thanks! I’ll try the heater method first. Cheers,


Hi Chris.
Last night I spilled tea with sugar on my white macbook.
the water evaporated but the sugar is still there..
how did you make it?

thanks :o)

How exactly did you do this ?

Did you close the mac book when the program was running , did you turn it upside down.

I have a similar situation and over night it doesn’t seem to be any better …

so I tried this and now the backlight of my display stopped working . 😦

I have a new ( refurbished ) 15″ MPB . And I didn’t even get a chance to get past the welcome screen when it got the water in the screen.

So I booted into single user mode and did a couple of :

yes > /dev/null &

And it started cranking along… Then after about 5 min the screen went blank and I thought I killed the computer …

I held down the power button and it turned off and on and the sceen was still black. I hooked up an external monitor and that worked and then I realised that the display is working but there is no back light 😦 …

Any ideas ?

I can’t thank you enough for this post. I woke up this morning and my macbook had massive bright splotch in right hand corner that I was really worried about. Did the same thing, checked out Apple, found out wasn’t covered, would cost fortune, googled my query, found your post immediately and have been running all sorts of programs all day. It’s reduced to bits of blotch now and I’m feeling a lot more hopeful I’ll have my gorgeous mac back.

Thank you so much. 🙂

Hi cod,

just opened up my mbp 17” to find a water bottle was not closed properly in my bag – utted & have a paper due in tomorrow which is quite worrying! writing this message on it at the moment so it seems to be working fine [not plugged in]. The problem is what looks like water between lcd screen and glass. All advice is telling me to turn off and put in a bag of rice which i m unable to do as need to finish end of term paper – no access to another device to finish it on and i m sure the tutor has heard the ‘i split water on my laptop’ story many times before.

For a newbie to mac’s – 6 weeks and a total novice in terms of handbraking, python, etc etc can you point out the procedures that i need to follow [that worked for you at least]

many thanks in advance

camroc 😦

To those wondering how to run the script, download the free app “TextWrangler”, copy paste this code in, and select run:


i = 0
while True:
i = i + 1

Thanks for your help cognitive, doing what you said cleared up most of my water.

i downloaded textwrangler
and its like some weird document thing that edits documents, like a big freaking spell check

i copy and pasted that, and theres no function to click “run” please help me 😦

its under the #! tab

I spilled some water on the lower right corner of my screen. It wasn’t much so I didn’t think it would do anything. When I got home I saw thick lines on where the water was. When I googled for a remedy, I found this post. I ran the scripts on two terminal windows, just as the commenter Rohit said and viola! It worked!

Thanks a lot!

Thought a water bottle was empty last night and accidently splashed quite a bit on the screen. I had a stress out, started reading on the internet and everyone was like ‘TURN IT OFF, PUT IT IN RICE. BE PREPARED TO WAIT ATLEAST A WEEK’. I couldn’t wait this long and then i found this method.
Got the two terminal windows going, fan maxed up and set it going overnight. Most of it’s gone now just one little light blotch. I have no doubts that over the 6 hours or so it’s going to be gone and totally back to normal.
GREAT TIP. Thanks! You’ve saved me a lot of worry and wasted time.

im a bit lost as to these 2 terminal windows

i opened applications >

opened utilities >

opened terminal – opened 2 new windows

and copy and pasted that code into them

yes > /dev/null

then i hit enter, NOTHING happened.

please explain to me what this terminal thing is

?? help : (

This is amazing. I spilt beer on it leaving a 2-inch rim at the bottom left. After 2 hours it’s half the size. I found that putting the MacBook on a cushion, closing the lid with another cushion inside and then putting a third cushion on top gave great results. No stains at all!

Thanks so much for this. the white blob on mY screen is becoming better. but as You might of noticed mY keYboard is kind of plaYing up esspeciallY ‘Y’.

bY the waY You don’t need to use the program he recommended. You can easilY just open up as manY programs as You can. like for instance open up Youtube and open 3 videos on three windows, open a video/dvd plaYer, open itunes open iphoto and preview. that should get the fan on high and the computer to heat up. and then just rap it around with a blanket.

mY screen still isn’t 100percent it’s probablY 30percent better.

Hey guys,
I am currently trying this… got the SMC Fan control at the highest it can go, and I’ve got as many apps as I can open running as well as a video on google video so the computer is a busy bee…
Will post later with updates, my screen damage is extensive so we’ll see how well this works 😦

thank you thank you thank you

my daughter just spilled water on my screen – the first time ever in 5 years.

Huge discoloured blob and people in other threads saying “you must switch it off for at least a week or two .. blah blah”

I cant afford repairs and the computer is my livelihood. I CANNOT afford not to be working for 2 weeks (it would take that long to get fixed as it has to be sent away)

I am praying this works and that I don’t end up with a screwed up computer – ultimate nightmare would be if I lose my data, as I have all my logs of hours work done due to be billed in here, plus tons of apps etc.

I could kill the little brat right now. My day is ruined.

[…] down again and searched online for ‘bright white splotch macbook screen’ and found this blog entry.  I read through the author’s similar experience and set about stressing my MacBook with as […]

Hi, glad I found this, I’m in the process of drying my MacBook out now, thanks a lot!

Thanks for the info! Been running 2 terminal processes, a dvd on 1/8 speed, a streaming movie on netflix, and the script in text wrangler for 18 hours. Temp has fluctuated between 78-84 C. The splotches are smaller.

Worked, just kept hitting replay on Avatar DVD lol

Thanks it worked beats paying 750.dollars 4 for a new screen the screen look great again thanks again

Thank you SOOOOOOOOO much! I was devasted yesterday when I opened my backpack and found that my water bottle had leaked onto my computer. My heart sank when I lifted the lid and saw a giant pool of water trapped under my screen. When I found your post… I have to admit, I still wasn’t too optimistic. But…… you, SIR…are a TRUE GENIUS!!! I could never say thank you enough for saving my computer screen!

I can’t speak for everyone but I can tell you what works for me and what didn’t. Here’s my story first…

I bought this stupid screen protector on Amazon made by SGP or something like that…Well it’s a “wet apply” meaning you have to spray the screen and then put on the screen protector…(never again am i doing this)

well the thing is that after i did that my screen had this bright spot on the left lower corner and the rest of my screen looks as if i turned down the brightness by 1 or 2 levels.

Well i read lot of post online suggesting me to do the “Rice in the bag” trick, it seem to work for everyone on the other forums. i went through ALOT of forums by the way. but the ONLY downfall with that is that people were saying it can take from 3-10 days of non-usage of the laptop. since i NEED my laptop everyday for work, that wasn’t an option. so i came across on this post so i gave it a try.

i tried the Python application but just like other people on here who stated they couldn’t get it working i didn’t really want to mess with that application too much because of the knowledge i don’t have about it.

So i read the first post where “Morren” stated that he used an application called “SMC FAN CONTROL”. so i downloaded it. (i also tried the terminal commands & got no results) Within 2 hours the spots went down about 10-15 percent. I do have a few applications running like Spotify and Netflix, a few tabs open like YouTube, Facebook, Twitter & GMail and also the Sparrow application open as well. So far so good.

Though the SMC FAN CONTROL application states that my fan is at 5936rpm and that the temp on my macbook pro is at 118F but started at 159F everything seems to be really cool/normal temp. I will update tomorrow or later on tonight or whenever it ALL goes away. Hopefully this will work and nothing else goes wrong.

Thank you for this post. It saved me alot of time & money.

Forgot to let you all know I’m using the latest Macbook Pro Retina. If that helps any to anyone. I know the Retina’s display is made a little bit differently than the older models.

Also the liquid that i spilled wasn’t water or anything, it was a screen protector type of soap. The same kind that looks and feel like Windex. The minute it’s swipes away it dries. It’s also clearish blue and also foams up a little when shaken up. Maybe it was their version of Windex, i’m not too sure. but the company is SPG Spigen i believe. Hope that helps anyone.

*UPDATE* Since i posted a message on this blog back on October 19th, today is now October 24th, the SMCfanCONTROL app had brought down my water marks to about 5-10% left. though i don’t leave my computer on all day like some users has stated, i do tend to put the laptop to sleep whenever i leave the house or go to sleep at night, so far so good, i think by tomorrow or in the next couple of days all of this will be gone. so i can confirm that the SMCfanCONTROL method DOES work, i can’t speak for any other advice that has been given on here because i have not tried it. though i heard the old “Rice in the Bag” trick does work for ALOT of people. wouldn’t hurt to try that as well. best of luck to everyone.

Thank you thank you thank you! I accidentally knocked over a glass of water onto my computer in the middle of the night. In my sleepy panic, I found your website. I downloaded smcfan, and have had it running for the past 12 hours, and my water mark has halved in size and keeps getting smaller. I’m keeping a ton of programs running in the back too, and keeping a temperature of about 70 Celsius.
I’ve kept it propped up on a pillow, with a cushion behind it, and that seems to be doing the job. As a poor student, I honestly can’t thank you enough

Dear Chris, thank you so much for this tip! I had spilled tea over my macbook but thanks to you my screen is nearly as good as new again! I made pictures before and afterwards (the screen even looks better than the last picture now):

Greetings from the Netherlands

Hi, could you walk me through step by step how you did this please? I’m not familiar with programming AT ALL and have no idea how to start this. Thank you.


Hello Chris,
Can you teach me exactly what you did to get rid of the water spots?? A water bottle spilled in my backpack yesterday and all over my macbook. My computer seems to be running fine but I just have huge water spots on my macbook. Can you teach me step by step? I would greatly appreciate it. Thank you so much


P.S, like many others, I didn’t know how to run the python script, so, I did a software update…plus I had some other windows going, one with Youtube, and a 10 hour long video going. It worked, hallelujah! !!! Thank you so much, again! I can’t thank you enough!

Thank You so MUCH for Help …. SmcFan Running on 81c constantly.

Thanks, Chris! This sorted out a gin and tonic disaster when turbulence on a plane soaked my keyboard! A few hours running everything I could throw at my computer sorted it out. Now… back to my G&T. Cheers!

Dude this was the most helpful thing I’ve came across! I just bought a new Macbook retina and water got behind my screen in the lower left corner 😦 but I downloaded SMCfan control and its going away! Slowly but it works!

will this still helpful after the blotches appeared for 1 week ? I was too busy to take care of it. And is there anyone can help me with how to run a python script ? I cannot manage to launch the program

Did you manage to fix it? I’m having the same problem right now.

[…] then got my shit together. I searched on my iPhone on how to deal with this situation. I found a great article that said I should turn on my laptop and run some things so that it will get the fans of my laptop […]

This worked perfectly for me, thanks very much!

Sorry if this seems like a silly question, but when running the program, do you keep the laptop open or shut?

Thanks a lot for the idea, even though it didn’t work in my case. I decided to share a few things with others facing this problem:

If you decide to run the Python script, make sure not to miss any white spaces before i = i + 1. I guess this might be the reason why some people doesn’t seem to be able to run it.

If the liquid contains salt/sugar, you are most likely screwed (what means that you have to scroll down a bit and read the rest of my reply…) but it’s still worth giving a try.

I’d recommend opening the script in 3 terminal windows : )

If you have a bad luck like me and even after a long time the liquid doesn’t seem to dry, there’s one thing left to do before getting a new lcd and it’s the only thing that actually solved my problem – opening the screen and cleaning it manually… It’s a difficult task, so if you decide to take the risk, you have to be very careful, but it’s possible. I achieved nearly perfect state of screen, besides one little piece of dust that got inside – still, taking into considaration the non-perfect enviroment I performed the task in, I believe it’s a great achievement anyway.

What you have to do is to follow a guide for your laptop’s model (in my case it was MacBook White A1181) to take your lcd screen out:

Afterwards you have to open it and clean manually – I followed this video, even though – unlike in this guy’s case – my screen had like 4 layers and I had to clean each of them…

Good luck guys and stay away from water in the future ; )

same thing happened to my notebook, but a week later the bright spot is still there.

Then go ahead and look at my comment up 😉

Wow, what can I say! this technique even works on the newest Macbook Pros!

A water bottle in my bag leaked out and due to the water-resistant nature of the bag material formed a nice puddle of water in the bottom of it while I was walking down the street. I only noticed because I felt a bit of water on my lower back. I quickly pulled my Macbook out of the bag and dumped the water out.

Long story short I was freaking out because I have had this Macbook for about 2 months and it cost me nearly £2000.

I put it in rice overnight which I think initially saved it as it stopped the water spreading into the machine too far.

I found this technique on my phone and after approximately 20hours the huge water damage stain on my screen has reduced so its nearly gone.

I am running the python script as well as SMC fan and exporting a 20hour video on adobe premiere!

Computer has been up to 75 degrees.


Same thing happened to me just a few days ago as well, and I’m just trying this out now
Hope it works out for the both of us

It worked for me almost competely gone now!

i tried to clean my laptop with a cloth, which was probably a bit too damp. anyway had a lot of bright spots. used smcfan for 2 days almost.
fast forward 15 days,
still have bright spots, not as many as i had previously!
what should i do? :O

Currently doing this on my macbook pro A1502. For those of you who want to try the script, you can try to do what I did.

1) Go to
2) Download the one you need.
3) Open sublime and type in the code:

i = 0
while True:
i = i + 1

INDENTS MATTER because #python. If it looks like this:

i = 0
while True:
i = i + 1

It won’t work because its not going to loop. After you hit the enter button after you type while True:, it ~should~ automatically do the indents for you. Its also case sensitive.

4) save file to desktop as

*You don’t have to save to desktop, but it’ll help you change directories more easily in terminal.

5) open terminal. It should be in your applications folder or you can search for it.

6) In terminal type in:
cd Desktop

7) In terminal type in:

It should now be running. Since I have the newer version of macbook, I’m currently running about 20 of the terminals because my laptop wants to keep cooling it down.

I see the indenting didn’t display here like I thought it would… But don’t forget the indent. =)

Anyone think using a blow dryer on the screen would work?

Use Prime95 (Torture test, choose most heat option).
Much simpler for heating up Macbook.

Where do we download this from?

Worked perfectly for my zenbook pro. Thanks a lot dude!

OMG! Thank you so much for sharing this! I actually had to call a friend to guide me on where and how to input that there code! I can tell it’s working and hear the fans going. My laptop was stolen and returned two weeks later to my neighbor who saw my message flashing across the screen that it was stolen and my phone number. I guess they were kids who were afraid they would get caught and didn’t think to sell it to a pawnshop. Anyway, the only thing wrong with it were the water blotches behind the screen which you have helped me with! Good Karma your way!

Hi All

I have just been reading this post, while searching for some way of fixing my water damaged Macbook pro.

Similar situation to many, a water bottle in my bag burst result: bright white blotch on the bottom of screen. However, rather than running the script I simply put a fan heater on my Macbook pro at it seems to be doing the job – I can’t quite believe it!
I had the laptop sitting on a radiator for almost a week then in rice for a couple of days all without much improvement. But the fan heater have only been on for about 45 minutes and the screen is already much improved!
I think it is the air circulation and the heat in combination that seem to be working.

I have a chromebook which has a small portion of the screen on which I spilt water. But in chromebooks I have no way to use python or handbrake a dvd. Any options for Linux? Any ideas would be helpful!

This 7 year old blog post saved my MacBook air! Thank you for sharing this solution. It worked perfectly!

i spilled milk on the new MacBook (Retina, 12-inch, Early 2015) which is the first macbook with no fan !!
any idea how I can deal with this milk spill?
I’m posting from it right now but the screen is an awful mess!

Recently had the same problem after a water spill. Found this post and was initially concerned following the usual advice to keep a water logged machine off. I did keep my Mac off for 24 hours and in a position that would allow gravity to take the water away from the most important parts (i.e. the bit under the keyboard!) but ended up with half of the right side of the screen covered in water spots. Got in touch with Apple who said this advice was fine for a machine that is working normally (i.e. your only issue is the water spots on the screen). Being that I was in a hot country I turned the air con off and left the Mac out to dry in between using any program that makes the Mac get hot. Worked a treat!

These liquid spill will make Macbook keyboard difficult to use press again sticky or stuck
Here The solution

Bad accident – my solution!
Hi all,

In my case, I put not properly closed iced tea bottle in my backpack. It was mostly empty and I thought the most of the spilled tea was absorbed by the papers I had in my backpack. I dried some drops of the liquid from case of my MB air . When I turned it on the following day (not suspecting anything bad), I was terrified. There was bright splotches in the middle and what was even worse – exactly 1/3 of the screen (it was literally a line between this part and the rest of the screen) was barely functional i.e. round bright stripe going through the middle of it (around 10 px wide), the rest of it was very blurry. On top of that, this 1/3 of the screen got its image reversed, so navigation was almost impossible and I am talking about the left part where many important menu options are located. I followed some of the advise here. First I decided no to turn my mac off(as some websites suggest) since it was already working I didn’t suspect any worse could happen to it. Second of all I followed some of the advice from this website. I installed SMCfan and put it to max. Second of all I placed my mac close to a heater (apple sign facing the heater). Close enough to get the screen warm but not hot. I turned all the possible apps, music etc. so the temp was around 40 – 50 c sometimes increased to 60 c. The fan was spinning like crazy thanks to the app. After one hour I noticed that the stripes disappeared – that was a good sign, since I was worried that it was permanent damage. Second of all the image in the 1/3 part started to be readable (there was still some funky colors but at least I knew there was some progress). Lastly after another half an hour the image started to twitch and became blurry again but I noticed that the reversed image becomes faint and starts to be overlapped by the correct image. Sometime later it was back to normal, with colors almost right. There is still some blotches, but at least I can start working again. I will give it another few hours to see if the blotches disappear but at least the screen is fully functional.

[…] Bright Splotches Under Macbook Screen From Water Spill […]

Thank you Bro, just happened to me, and your script did the job very well.

Is there any chance anyone knows whether or not this might work with the 2017 newer macbook pro? Have had it around 90 degrees for an hour, maybe I’m just being impatient! (Help please!)

Hey Rose. Same problem. Trying to fix it currently. Did it work for you?

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