I have made a lid from aluminum flashing using a die that I made from plywood and a couple of c-clamps to do the pressing. If you are interested, pm me and I can provide step-by-step instructions. The lid I made is on the IMUSA mug; the second pot from the right in the attached photo. The pot I like best is the IMUSA mug on the left; I used the lid from the grease pot for the smaller IMUSA mug. It fits perfectly, the pot holds about 0.7 liters.