This stuff

 

Over the years, I have seen many posts on lists, etc., about how so-and-so was lamenting that his ACC went bad and the container was still half, three-quarters, etc., full. I bought this at my local hardware store, maybe 250 paces from my front door in Brooklyn. It's not any special hobby formulation. I have had it open for about two years and have seen zero degradation in its effectiveness. I don't know if it's the "Professional" formulation, luck or more likely, it's good stuff. The cap is notched and is quite secure. Maybe that is the reason. Regardless, it has lasted and I am here to report that I am a very satisfied customer. Hopefully, your experience matches mine. That is all...