This issue is getting more common each day with older LCD screens. You can see some "lines" and "marks", this is commonly called vinegar syndrome. This happens when the LCD's internal polarizer films, which are made of acetate, break down into acetic acid.
The only solution is to remove the damaged polarizer film with a new one.
In this video we are going to do this process for an older laptop, the iBook G3 Clamshell released by Apple in 1999.
If you need more information or want to discuss further, we are here: https://www.replacethecaps.com/community/ibook-g3-clamshell-with-vinegar-syndrome-t16.html
This is the link for the 135 degrees polarizer film replacement from Aliexpress: https://www.aliexpress.com/item/32825723414.html
The audio for this video has been generated using AI: https://elevenlabs.io
Timestamps:
00:00 Welcome and showing the problem
00:20 Taking it apart
01:51 Removing the damaged polarizer film
02:40 Cleaning the old glue
04:27 Last check before installing the new polarizer film
06:10 Installing the new polarizer film
08:35 Putting everything back together
09:50 Checking the result