As for the use of cooking oils attracting rodents, for me the debate is still out on that. Some years ago my workshop would have a field mouse or two find there way in during the colder months. I would store my smaller bit and pieces of leather in an upper cabinet above my work bench, the only thing I ever found chewed on was some blacksmith side pieces, never and raw leather or treated pieces. Mind you I never had any leather treated with cooking oil there but there were pieces treated with neatsfoot oil, lexol and some other products for leather.