Say I have 9 otter anal glands that have been aging in mink urine. How much glycol should I add in the blender to make them freeze proof? Don't want the lure watered down but I definitely want it freeze proof. Should I also add sodium benzoate or no?

None. Especially with glands and urine. I wont put glycol in any lure or bait.

Doesn't glycerin add a slight anti-freeze affect?

Yes glycerin for antifreeze

So how do you keep your lure from freezing then?

Glycerine does a good job.

Glycol will kill scents over time

So it would be better to use glycerine in a gland based lure than glycol?

In my opinion, yes.

Thank you, duly noted

I use to use glycol in my deer scents when I first started making them. I used it for about 10 years then around 2000 I switched over to glycerin. I still have some of those old deer scents with the glycol from back in the '90s and they still smell and work the same as they did back then. I will say that I was using glycol in my cover scents, cedar, pine and dirt at the same time, and the odor would weaken after a few years in the bottle, so I stopped using it in my cover scents.

Contrary to the fad that has been put out there , Today's glycerin oil , the way it is processed , will kill some natural materials over time , it is selective . Back in the day when glycerin oil was processed from animal bi-products it worked great , the 'Ole folks knew it and used it with great success , Johnny Thorpe being (1) master that knew this fact . Today glycerin oil is vegetable processed and more fake like other fake Art. fake materials today that the animal's do not respond to , and it is processed Not to be attractive to animal's .. The 'Ole time glycerin oil was great material , as was sperm whale oil and seal oil once was . The animal's respond by not having anything to do with it in certain compounds , In some cases nothing to do with it at all .

Today the same is Not the same as it Once was , to the animal , To humans it matters Not to our sense of smell , but certain animal specie's does not like the effects that today's glycerin oil reacts within certain compounds , as animal's did with the 'Ole glycerin oil from 40 years ago back . This has been a known fact by Tests of different compounds and the animal's response when checking results over many months / years of testing .
Manufacture's of glycerin oil today process it to Not be animal attractive , same as many other materials . It is the rules with the FDA and others .

Watch out for certain manufacture's that process glycerin oil today , there are anti-trappers and hunters that help manufacture glycerin oil , more so today than years & years ago .

I don’t make lures or baits so I have no skin in this game. But if you want pure glycerine, go to a pharmacist and buy USP grade glycerine. This has been tested. If it says 100% on the label, then that’s what you’re getting.

Nope , USP grade is also Vega grade . same as FDA approves ALL today , unlike years ago . the 'Ole folks are gone .
Natural is fading away , Art. is coming like a freight train get ready to get on , no caboose though at the end just maybe a blinking light , maybe ............................................................. :

Nope , USP grade is also Vega grade . same as FDA approves ALL today , unlike years ago . the 'Ole folks are gone .
Natural is fading away slowly by laws passed , Artificial. is coming like a freight train get ready to get on , no caboose though at the end just maybe a blinking light , maybe ............................................................. :
this has been coming for some time now it has started with big game first , but will arrive down hill to other animals one day