On Monday, October 15, 2012 12:14:22 PM UTC-4, Existential Angst wrote:
Assuming they are still dry, of course. A local home center guy said yes,

prolonged exposure to air renders it unusable.

How old is old? How to test? My own little spot tests (small mounds on a

board) are really crumbly, but I haven't compared it to fresh stuff yet.

--

EA

If it's still loose then it's probably usable for most home projects. When it absorbs too much water from the air it turns into a bag sized rock.