When I was still in Ca. I had some real problems finding the stuff. My local market had some very old cans of the stuff and I bought it all. Then they no longer carried the stuff. We had an ACE in town but I never thought to look there.
Now in the Vegas area we have no ACE hardware stores that I have found and none of the markets carry it. Buy it when you can find it, I always keep my eyes opened for it and it's A good thing to have on hand when you need it.