This topic has been discussed several times here....Should a product like olive oil or motor oil be used as a leather treatment. My own personal opinion is, no. Olive oil can go rancid rather quickly once opened and being familiar with that smell I would not put it on something I was intended to wear. You can prolong the life of olive oil by keeping it in the fridge..... but that isn't too practical for a gunbelt and holster. My response would be the same on motor oil. The petroleum will quickly degrade leather, causing it to debond and just fall apart.
All that being said, that's a nice job on the holster.
JMHO any other input?
Dave