I need actual advice/realistic solutions and not people suggesting baby wipes.

I'm amassing a larger Street Sharks collection and quite a few are dirty. But they're made out of this weird rubber shit and I know that if I use alcohol or regular soap it could dry it out and damage it or crack it.

What do I use to whiten up spots and clean up the overall pieces so they aren't permanently fucked and dried out?

Also, street sharks thread I guess.