Al,
It does not go "bad"! It does dry out and will need to be mixed with DNA and then agitated to get it to break down and combine with the DNA.
I've had to "crush" up mine on occasion using a screwdriver. Once I got it usable I put a couple of SS ball bearings in the jar--I try to give 'em
a good shaking every now and again (when I remember).
Bruce