after several years sitting in a container? Have used glycol the last 5 years and have replaced and disposed of what I had
left every other year. Yesterday, at Pa Convention, the fellow that I bought some new glycol from said he had never heard that it loses
it's ability to prevent freezeups after several years. Can I use "old" glycol until gone?

Put a cup of the old stuff in the freezer and find out!

Great idea BigBob, I think that I'll put a handful of peatmoss sprayed with "old" glycol in one jar
and another handful sprayed with "fresh" glycol in another jar. Thanks

Problem you have to watch with it is that it will attract water. Not much a problem if your using to it at the set to freeze proof. Can be a minor issue for luremaking

I’ve always bought new every year. The unused portion from the previous season always has a weird smell.

What Rob said! Although, being a tight arse, I always kept my left overs, and used them with no real problem, now that I know it smells, that bugs me! I played with a jug last fall, and left the cap off of it, in a few days, I couldn't smell it anymore. I used to buy glycol, but have went to glycerine these days, because they are the same price. It used to be glycerine was much higher. Still have a couple jugs of glycol around yet, and have never had it develop a smell with a full jug. I'm convinced that it must oxidize in the jug from not being full, just like wine will do.

I've never had it lose it's effectiveness from year to year for freeze proofing!

I buy glycol, glycerin and mineral oil by the drums as do most larger distributors and lure makers. If the batch is current and dated fresh it will last for years if stored properly. We run about a drum of each in a year more or less. Never had any problems with trapping use or formulation work. I doubt the Glycol would lose its effectiveness as an anti freeze additive even if it is old but if it develops an odor I would be concerned to use it.

P. Glycol can sour/break down if very aged or stored poorly. It can develop an odor if there is some chemical reaction with the stored container or due to extreme heat exposure. I bought out a fella years back that had some P Glycol in a 5 gal metal pail that appeared old by looks of the container it was bad.