you need to know what kind of leather you have, generally, protected or
unprotected. and what the manufacturer recommends to do in terms of
cleaning. Use just distilled water for the first round is not a bad idea.
if it's kind of dirty, then use a little bitter soapy water (just ivory soap
). then you need apply leather conditioner.
the best brand is leather master, there are many alternatives out there.
check them out at amazon.