Evaporust gel on battery contacts.

[vaklaff]

While battery goo can be removed quite easily by vinegar or baking soda (*), depending on the battery type, rust is less easy. I try to do it with sandpaper but I think it's too crude and mechanically risky. Are other approaches in wider use, e.g. gels like this one? And any suggestions on protecting against further rusting?

(*) any other tips, BTW?