I use my both of the stampin'Mist and stampin' scrub from SU! to clean my rubber stamp. It is much easier than just using water because there are some inks that you can't really clean it just with water.
Mostly use water, but if it stains on the stamp, I use Stampendious rubber stamp cleaner, or Inkssentials Cleans it all purpose stamp cleaner. Except Staze On ink, then I have to use Staze on cleaner.
Yeah I use that stampin'Mist and stampin' scrub from stampin' up... I used to use staz on cleaner but the sponge head becomes so dirty.
OR just simply use baby wipe, that works perfectly too.