I've made a wet hand tutorial, partly for practice partly for fun, but it's a really good tip. Basically you just get a cotton glove from an medical store or pharmacy, they're mainly used by people who are allergic to latex. I've also heard of people doing the same with photo-developer glove, there very similar. Or if you're really pro you can just buy a smudgeguard, but they're to expensive, especially if you need to ship them overseas.
I know I'm not the first to mention this tip, but I figured it out for myself before I saw other people had similar ideas. It's in Swedish but hopefully you can get the gist of it from the illustrations.