I unfortunatly do not yet have a leather holster but plan on getting one soon. I can tell you that I use a mild leather cleaner I purchased from Harley Davidson which works great on my black cowboy boots. I'm not sure how it would work on rawhide but I dont think it would be a problem. After I clean with the HD cleaner, I shine them up with Parade Gloss from the Kiwi company.
I know boots arent holsters but I cant imagine the leather used is much different. Hope this helps.