Yes, it has been very useful as a learning tool. I enjoy looking at cullet and I feel like it's a really nice asset to a collection. To me there is more to marble collecting than just the orbs of glass, I like the whole story. The pictures of the old factories, the broken pieces of oven brick and machinery parts, the stories and digs, the packaging, advertising, and all of it ties together to make a much more interesting presentation than just some pretty glass balls. Some of my favorite marbles are the ones to the left in a square cardboard box with dirt still on them from the old Pennsboro Alley factory that I got from Mibcapper. It's the history of it as much as the beauty. I hope that by the time I can retire (if I ever can), I will have enough interesting pieces to build a modest but complete "exhibit" about each manufacturer and share it with everyone either by going to shows or by having it in a small museum or ...?
But that's why there is the little akro leaf dish, the gearshifter knobs, the cullet, the funnel and pintle from Akro, and stuff like that. All my cullet is from Pennsboro Alley, Akro, and CAC. I'd like to get some from ravenswood, Cairo, etc... if anybody has some they would like to sell.