"...how smooth it has to be to use wax..." More about leaving tons of lint behind from the cloth. Neat foot oil is made from cow feet and bones. Made for conditioning, softening and preservative agent for leather. You don't want a soft holster. Causes the firearm to droop. Olive oil on leather will cause premature deterioration and oily spots that will not come out. Oil in general isn't good for leather. Net search 'Olive oil on leather'. 2.82 million pages arguing.