The best thing to use is one of the many vinyl cleaners on the market, and trust me there are a lot, Starbrite, Meguires, 3M all make good ones , stick with a good brand name one, also READ the instructions on how and where you can use it, also when your done cleaning it follow up with a good vinyl conditioner, so if it happens again it will be easier to clean and help keep the vinyl soft and supple, so it wont dry out and split or crack, cheers :-)