Aside from removing the corrodant, corrosion can't be removed, because by definition, it's already gone. problem is that some corroded materials aren't very conductive (eg, Rust vs Steel ).
You can get a fiberglass pencil for removing light corrosion. They work really well, and are light on the abrasive to avoid removing electroplating where possible, but since corroded materials and rust are usually lighter, these are a suitable alternative, and cope well with shaped surfaces.
eg:
As was noted, corrosive liquids escape a tightly sealed battery. They travel up the battery contacts pretty effectively too.