I don't think dry cleaning or full immersion in water is a good idea. You can get proper leather cleaners for the leather itself. To keep the leather supple, again you can get proper leather treatments, or, a little tip - Neats foot oil, available from , erm, what do you call the places that do all the bridle stuff for horses? Those places, anyway, looks after leather a treat. Hmm, not sure about the liner, yes, perhaps a suitable anti-bacterial spray as you said.