Someone tried to clean my Sony smart TV (which is not supposed to be cleaned that way) with glass cleaner and now it is full of white stains. I've tried gently rubbing it with a dry cloth but they don't seem to go away. Is there a way to remove them?
Most sources I reviewed online suggest using only a microfibre cloth slightly dampened with a very dilute solution of mild dish-washing detergent in water.
Avoid any products containing ammonia or alcohol with new flat screens that are plastic rather than older models that used glass.
Dilute the soap 1 part with 200 parts of water. That's 1 drop of detergent to ¾ cup of water (200 ml). Blue (coloured) Dawn™ is an excellent detergent for optics as it has no additives that will leave residue.
Use Light pressure to remove the "stains" with the dampened microfibre cloth. Heavy pressure will possibly damage some pixels. Pretend you're rubbing your eye as a guide to the amount of pressure you should use.
If that does not work, it is very likely that the thin plastic coating has been damaged beyond your warranty conditions for repair.