I tried contacting Sawyers through their web site twice, no response - disappointing >:(. Thought someone here may know the answer.
I had an unopened spray bottle still in the box from last year. I put it in the garage for the winter, and found it partially frozen last month. You could hear what sounded like a big ice cube floating around in the bottle.
Still good?
When it comes to ticks, I'd just get some new to be on the safe side.