In a recent linotype score, I picked up a few ingots that were different from the rest.
They weigh +/- 9 lbs. each but are cast in such a way that they can be snapped into three separate ingots of 2.5 to 3 lbs. each. On the top they are marked "IMPERIAL" and lightly stamped on the bottom they are marked LINO PLUS.
I suspect they are designed to be added to printers lead for some reason, but I would appreciate someone's more knowledgeable input.
Thanks!