Finally bottling up oil and leftover chunks from a batch that festered for 3 years. Wondering if it’s necessary or beneficial to add glycerine to either? Will be used in freezing temps. If so how much, or anything else?
Thanks for any advice.

I don't think it's necessary to add anything .

No. I did the first time I experimented with a BTO based lure. BTO and glycerin will separate into two layers, the glycerin won't separate out clear, but if you let it set you will have two distinct layers. Also BTO will not freeze at the temps I have used it at, down to about 20 below. At cold temps like that it will gel into a consistency almost like toothpaste rather than a liquid, but it doesn't get hard yet.

Ok, thank you. Will leave the oil as is.
How about the leftover chunks and liquid? I think I saw somewhere on here that that leftovers can be used as bait.
In general how much glycerine can/should be added to baits to help prevent freezing and drying up? Any suggestions on ratio? Or anything else to add?
I did make a test dirt hole with the stuff as is to check interest in a spot where I regularly get pics on coyotes, bobcat and coon.

Personally I'd only add it if you see you need to. I'm not a fan of glycerin unless it's absolutely needed. If I can use an ingredient that will do the thing that glycerin will do ( lower the freezing point or act as a conditioner) and add to the attraction of a formulation I'd much rather do that.

Update - test hole with leftover tail pieces yielded one grinner first night.
They seem to be moving into the area, no pics or catches of any first 5 years here, but got 2 last year in fisher boxes.

Update:

Test hole results - I think I’ll mark this down as a positive response!

I'd say! Very nice!

Was that the tail pieces or BTO? If tail pieces, it matches my experience with them.

Just keep in mind the amount you put down a hole can directly affect their response.

It was about a golf ball size piece of what was leftover in the bottom of the jug from making tail oil, so mostly bone and skin.

That's a good response