Zor,

Hobbylite filler should by no means be hard when you open the jar. It should be a thick, spreadable paste. If it's hardened, then just give us a call. I have a few jars at home that have been sitting on the shelf. They aren't hardened, but are a bit stiff. You can rejuvenate it if it's not hardened by adding water a few drops at a time, until it's at the consistency you like. If the material in the jar is completely hard, though, don't bother. It's not worth it, and it will likely not stick well if you try to apply it. Call us about it, and you'll be taken care of.