Sounds like it got damp some how or way to hot. I had bought a jar one time that had some peices that looked like little rocks in it. If you try to dip a heated jig into it there will be a big blob of paint on the side that hits one of the little rock type pieces. I returned mine to the store for another jar. If it was crushed back to fine powder it should be ok. But may be hard to do. I always check each jar before I by in store. Never had any trouble when ordering online through Barlow's. Like the others have said keep it inside and not let it get damp or to cool or to hot.