Conditioning and Preserving Leather
Detail, Leather Knife Roll, Black
The natural oils in leather serve to lubricate the fibers and resist the penetration of water. These oils evaporate or are washed out over time and need to be replaced to keep the leather strong and supple.
If the fibers in leather are allowed to become stiff and dry and brittle they will begin to break and the leather will be permanently weakened.
Should I watch out for neatsfoot oil?
I don't know. Pure 100% neatsfoot oil has long been used to replace these lost oils. I could get some flack here but I've read that neatsfoot oil should be avoided. That both neatsfoot oil and the tallow often used in leather dressings contain salts that attack the leather fibers over time. In addition these animal fats support the growth of bacteria and fungus that will attack the leather. The mold and mildew often seen on older leather comes from this kind of growth. I don't know if this is any more of a problem than any issues the petroleum based alternatives might introduce but, for now at least, I'm going to stay away from neatsfoot oil. I have some leather stuff I used to dress with neatsfoot oil that now has that distinct mildewy growth and odor.
I used to make my own leather dressing
In the past I made my own leather dressing as a mix of beeswax and pure neatsfoot oil. It is sometimes recommended that lanolin be added to the neatsfoot oil as a conditioner. I'm a little leery of this practice and haven't tried it. Lanolin has a tendency to migrate to the surface of the leather and leave a greasy residue that is easily transferred to any absorbent material it comes in contact with. Lanolin is produced by the sweat glands of sheep; it's the greasy oil that covers the sheep's fleece.
Now I use Pecard Leather Dressing
I no longer use the neatsfoot oil and beeswax mixture. For the oil tanned leathers I'm partial to I like Pecard Leather Dressing which I understand is a mix of beeswax and other waxes in a petroleum based lubricant similar to vaseline. I like the way this stuff goes on and it sure beats the trouble and hazards of mixing my own dressing. Pecard makes a full line of products for various applications. If you don't want to buy factory direct, David Morgan, where I buy the kangaroo skins I use for lacing, carries Pecard Leather Dressing.
My objective with my leather is to keep it supple and extend it's useful life, not to preserve it forever; that's a complicated problem with no simple answers I'm not going to address.