Get some Lexol vinyl/plastic cleaner/conditioner.
Check the Detailing FAQ section for more info on a bunch of products.
btw, I wouldn't use just a wet towel to clean it. Gotta use somethin' that protects it.
2004 E60 530is, Delivered 12/12/03, TiSilver/LGrey, PP, SP,PS, PDC, ACC, FRS, Step, Xenons, clear bra, body colored rear inserts. (Retired, 1983 henna red 320is)
2004 Corvette Z06 Commemorative Edition