[skeet]

I don't know that I agree with the practice any longer but always left a bullet in the mould. Now I only have about 30-35 moulds and just took one off the shelf that had 2 bullets left in since at least1990. It was a Lyman 429-421 mould that I really didn't have a need for . Sold it on ebay and it had no rust except a very light amount on the top of the sprue plate...and I lived in the land of humidity (Eastern Shore of Md). I've never had a rust problem but with all the rust preventatives out there these days..Do as Adam does..But I would not use a metal coffee can. BTW don't worry about swaging rifling into the slug if the foster type..Not worth the bother.And don't go with a Hard alloy for the slug. I also think the Lee Moulds are cheesy but I have a friend who uses them religiously..with great results And then I have NEI and LBT moulds that cost more than Lyman and RCBS. I think they are a bit cheesy too