Take it apart and clean it? Your UMD drive could be SOL, I don't see how it could get to such a state that it can't read. They don't make a lens cleaner for PSP's (that i've ever heard of), so your best bet would be to take it apart and clean it that way. I suppose you could try w/o taking it apart but that may just cause problems. Another alt would be getting compressed air and spraying it in the general direction of the lens, but that's probably not wise.