Most Hobby stores have all kinds and sizes of tins, as to shops that sell crafts. Go to The Tedd Cash Products website to see all the various size and shaped containers he sells for such stuff. I have a brass can the size of a percussion cap tin, in which i keep the extra caps. I have two brass tins that are about 2 1/2 diameter around that I use to store dry pre-cut patches, and lubed patches. I have a large tin he sells with a magnifying glass that holds my flint and steel, charcloth and hemp rope for firestarting. MY tin for actually charring cloth is a former electrician's tape can that has had all the paint burned off, and a small nail hole put into the center to allow steam to escape during the process.
Most shooters make do with whatever they have, or can scrounge. Most don't buy actual tins. The members here have given you a good idea of the wide assortment of tins that have been re-used for these purposes. There are as many other sources as their are sources. I have not yet used an old shoe polish tin for this kind of thing. Its been awhile since I bought one of those large tins. I have been using a polish that has the consistency of cold cream, and comes in jars with metal screw lids. Its very fast to apply to shoes, dries quickly, and and polishes well. I am going to have to make a metal note to do some comparison pricing on that polish vs. the older kind in the tins.