Thanks for the comps. I used it for years and still have about two pounds left. Unfortunately it is seven years old as I brought it over when I immigrated. Back at home we had a gem and mineral show and there was a palaeontological booth that I would pick up a big tub from every couple of years. I have not found a supplier where I can pick it up in similar quantities. Milliput is just more cost effective over here.
Where's "over here" for you? Might be someone who can get it to you for a reasonable cost. You certainly sound like you go through it fast enough if you were buying a big (5 pound?) batch every few years.
I love the stuff but it took me nearly a decade to get through the last five-pounder I bought, these days I', less ambitious and stick to the little 8 ounce ones. The stuff does keep forever though - that ten-year old set was getting kind of hard crusty for the last few years (mostly owing to my own bad storage habits) but hitting it with a blast from a heat gun or even a hair dryer before mixing softened it up to normal no problems. Your seven year old batch ought to be good still to, even if it doesn't feel like it any more.