Found two bottles from a three pack unopened, are they still usable or do they go bad?

Negative. They go bad.

Give it away to one of your hunting buddies, and if he comes back with a big buck and thanks you, then you'll know it's still good!

Smell it ! It's still good.

It’ll work, have used it successfully many times in the past. However, a new bottle is cheap.

If it has a salty taste, it has gone bad.

If its from last year and it hasn,t been open than it is still good. But, throw it out if it has been inside your hot truck or garage during the summer months. Extreme heat will make it go bad.

You guys think all those bottles at Walmart or your LGS were shipped in a refer truck? I be they've seen plenty of heat both there and in storage. I wonder if that's why they don't work that well.

I've never looked and examined a package, but look for an expiration date somewhere on the package.....I'm thinking you won't find one.

I've used tinks and had deer come in and not be spooked, and the one I like to use now is made by "Trails End" brand.
I've had bucks come in raise their heads and flare their nostrils. They would then just walk away.....More like out of curiosity.

Is it 'natural' or 'synthetic'?

If synthetic...it will last longer than natural products.

The trouble with natural products is you don't know how fresh they were to start with. And unless there is some date code on the bottle/packaging....if you even got a product made last year. Retailers don't throw away the left over scents that didn't sell the season before.

I suppose it also depends on how you intend to use the product. I wouldn't use it on a drag rag....or scent dispenser, but it won't hurt to pour it out in a mock scrape.

All natural deer products degrade with time (very rapidly once exposed to air). And it's not the urine that is appealing to a buck anyway, its the Estrogen/Pheromone content (if any) that tells them there is an estrous doe around.

Considering how much most folks spend getting ready for deer season....it would be a safer bet to just buy a new bottle of whatever concoction you prefer.

Personally, I don't use scents. Much preferring to keep and attract Does in the area...which in turn brings the bucks in. I have no interest in watching young/satellite bucks curiously sniffing a cotton ball hung on a limb....and more often than not...that's what you'll get. The older, breeding bucks are trying to lock down a real-live doe, so do all you can to keep Does around. There is no substitute for the real thing.

I'd use it mainly for placing in an area with long shot or viewing. That way if works great, if not then it wasn't close to my real target area. But as much as most spend on deer hunting another $9-$20 should be a drop in the bucket.
What's I'd really like to know is if that $45 Conquest VS1 estrus scent works. I remember years ago before that brand sold to the big commercial entity it was $10.

it's piss.
it was bad when it squirted out of the animal.

seriously, i'd use it.
i've been using on bottles i bought on clearance for 25 cents
5 or 6 years ago. someone tell me, what's the expected
life of a small bottle of piss?
professional trappers use bottles of piss that's years old,
and catch all kinds of animals. it's the curiosity factor that
does the work for deer or any other animal.
no big mystery or magic about it

I kept a tarsal gland cut off a good panhandle deer in a ziplock back in the freezer for several years, would take it out and hang from a tree branch and had all sorts of deer (both bucks and does) come to check it out ... put back in ziplock and back in freezer until next year ... my wife finally found it and threw it away ...

agree with maximum, it's the curiosity factor on most scents, especially something that aren't familiar with ...

It’s rabbit piss. Don’t know the time frame for it becoming degraded.

After it went to that brand I tried some. Had several bucks walk right by it and never ay any attention to it and most were down wind quite near it. Decided I had wasted my $. i did kill a 5 year old 12pt quite a few years ago that came in where I drug a drag rag with his nose to the ground on the trail. shot him as he was smelling the rag hung bout 2.5 feet high in a small mesquite tree at 150 yards. from the tracks in the mud that morning he had followed it about 120 yards before I shot him. That ws special golden estrus. I have also killed deer that came in to Tinks 69 that was at least a year old

^^^Pretty much sums it up right there.

When I hunted Lampassas I had a bottle that had been opened many times and it was probably 8 or 9 years old. I was in my tree stand and dropped the dang thing from 16' up and it went everywhere when it hit the ground. That morning I had an 11 point and a 9 point walk right up to the bottom of my ladder for a sniff. Got it all on video and those were the two biggest bucks I saw all year.

I've got some leftover Tinks, never opened. 'Gonna' try some behind the house to see what happens. I'll add, I've used Tinks for years and had success with deer coming to check it out. Fresh bottles smell like deer pizz just like old bottles. I've got a pretty good sniffer and I cant tell any difference between old and new.