Im currently doing a test with a substance known as OxyClean (youve probably heard of it) its like crystal stuff which your dissolve into hot water.
I put some of int in a bowl and let it do its job, and i put a key in from the rather yellowed pc keyboard. The bottom part of they key is pure white, but from half way up all way round it is pure yellow. Its strange, i had the computer for 4 years since 97 till 01 and it was perfect condition. I got new computer and the old one moved into my brothers room. Within months it turned yellow. Its because his natural environment is dirty. Doesnt polish or dust or anything. So obviously, thats hte nvironment in which compys go yellow, with dust and dirt. It cant be all about sunlight, i mean when i had it it was in a corner where the sunlight always shon on it. Was still pure white. Went into bros room in a corner where it doesnt get light, and about half a year later after the dirt and stuff, its yellow.
Anyway, ill let you know how the oxyclean test came on. If this stuff can make a black copper coin become shiny copper again, it should get the yellow off hopefully. Anyway, lets go see how it did, its been sitting for 10 mins now in a hot bowl of the stuff. Back in a few