When I bought my PSP, I got a screen protector. One of those bits of sticky plastic. Anyway, it was getting old and was peeling off so I removed it this week. It's left a dust collecting layer of sticky on the screen that I can't clean off. I've tried water and soap, and that's not shifted it. Any suggestions what I can use without damaging the screen?

Vinegar will possibly dissolve it, though try using a cotton wool bud. Though a mild non smokers toothpaste might be able to help, try it gently.

old engineering one
is the good old lighter fluid ie the petrol one

and will remove letters from keyboards and things like that

so use on a cotton bud