I chopped up a bunch of old beaver castors I had in the freezer and ran them through my blender adding only gliseron to it to make it pasty. What else can I add to make a good attractant to use at a bobcat or fox set. or will the castor work by itself.

As a change up to my flat sets i'll use just straight castor. It works well by itself

I make something I call Coon Berry for my dps it's a sweet lure works well for me and it's cheap to make a gallon, haven't made any predator lure yet, will be following this

I'm looking for something to add to my beaver castor that would make a lure for bobcat's and fox.

Muskrat glands and/or skunk essence.

Add nothing to the castor except maybe some vasolene and use it as a "RUB" attractant ABOVE you set.

Castor and fish oil will attract a heck of a lot of fur.Just add a carrier and a base of your choice.(i think vaseline is the worst thing you can add to lure.)

Depends how your going to use it Boco.I make all my own lure and have done so for many years.Its a good additive if your going to use the castor as a SMEAR lure,,ABOVE the trap,like I stated.I agree that I wouldn't add it for most lures.Also a good additive to Quill to be used a smear lure.Any PRO lure makers in here that read this can correct me if Im wrong,,but it works for me.

Vaseline will dry up on the outside and seal in odor. Boco is giving good advice

Weasel Musk

Also holds up to snow and rain and wont wash away.Has pros and cons,,just like anything.

Asafetida

Good for chapped lips also. A little castor and Vaseline. LOL