Recently i noticed quite a bit of deposits on the positive battery post. It is that whitish/greenish stuff that usually appears on older, neglected cars' battery (at least that's how I saw it so far). I was quite bummed because I always take good care of mine...
Anyway, the question is: what's the best way (and material) to completely remove this crap and what can i do to prevent it from happening again and corroding the cable terminal?

 

Hot water and a toothbrush.

Vaseline to prevent it coming back.

 

Take care not to flick any crap onto you or your paintwork, though.

 

WD40 on the terminals works ok too.

 

Alka-Selzter and a tooth brush. That, or a wire brush. i would spray down the engine compartment in the places that the stuff has fallen over to, so it won't damage your paint or anything else inside the engine compartment like Gomez said.

as for stuff to not have it return, you can buy an anti-corrosion lubricant from pep-boys, auto-zone or any other auto shop for like a dollar. The other way around it, is that there are some terminal washers. these washers are made out of a special cloth material that won't let the terminal corrode and are also relatively cheap.

 

Hot water will dissolve the white stuff, just make sure you don't short circuit anything