This is a discussion on Leather Knife Sheath Oil? within the Edged Weapons forums, part of the Gun Forum category; Many say to use Neatsfoot oil on leather.
Many say to use Mink oil on leather.
Now, we use mineral oil on our sharpening stones ...
I like to use saddle soap/leather conditioner on my sheaths. If it is a sheath or holster with a scuff in the color I will use Kiwi shoe polish in the color of the sheath, followed by treatments of leather conditioner. This has worked well for me. On my collection of Khukuries I find great results useing kiwi polish and saddlesoap mixed together to create a deeper penetrating conbination on the sheaths.
I stay away from the oils that can soften the leather too much and have adverse affects on leather and stitching.
I do use mineral oil mixed with a little clove oil for scent on my carbon steel blades and BLO on wooden khukuri handles.
Stay away from petroleum based oils. Pure 100% Neatsfoots oil used sparingly is OK. Followed by a top coat of good wax to protect the finish. Gus provided this link to us in another thread on the subject of leather. http://www.jarnaginco.com/leather%20preservation.htm
It's been a while since I've used any, but there used to be a similar product, as above, called Snow Seal. I used it on my climbing boots over thirty years ago. I still have those boots. They were a suede or rough leather outer and I had to work the seal in pretty thoroughly. The leather on those boots is still good. The rubber soles and padded ankle are cracked.
I use both Pecards and Neatsfoot. Both contain petroleum distilates as portrayed on their ingredients listing. Neatsfoot Oil will darken the leather a lot more than the Pecards. I use the Pecards in the paste or wax form very similar to Saddle Soap. While the Neatsfoot is in liquid. I just follow the instructions.
I think the biggest thing is follow the directions. Most of the bad leather I see has been the victim of over applying leather treatment of one kind or the other. I agree that a 100% avoidance of "petroleum based products" is almost impossible. The stated problem with petroleum oils is that they eventually will break down into solvents and will work against the leather.
No good reason to treat your leather with motor oil or mineral oil for that matter.
You can go to any Red Wing Shoe store and get a bottle of their boot oil. I suspect it is a high grade neetsfoot oil but I use it on knife sheaths,holsters,boots,slings,ect. They also sell an applicator bottle for it that is very nice to apply it with!
I use vegetable oil on my saddle and work boots. No problems so far.
I asked an Amish harness maker years ago, when the kids had ponies, if it were okay to use vegetable oil. He advised against using vegetable oils because it attracted rodents to the leather and wasn't really made for that. So that is something to consider. That was the first time I was introduced to Neatsfoot oil.
the best ive found is the Aussie wax/oil made by Feibings. Alot of the above mentioned treatments WILL soften the leather over time and actually start to break the leather down.
Alot of the treatments should be used more for a "cleaner" then an actual preservative.
Conventional wisdom is to use the same oil that the leather was tanned with- if vegetable use something vegetable based, if animal use that type. But neatfoot oil is used to soften leather, not just preserve it, so I would avoid neatfoot if I wanted a stiff sheath. Hard to go wrong with a modern wax product, at least I've never had a bad experience, but those are made for a wide variety of purposes.
From my hoss-y days, I can recommend saddle soap for bring up a good appearance on fine leather, and I think it preserves as well. Try that and you are bound to be pleased.