Large sheets of brass should be annealed in a properly constructed muffle or furnace; small pieces may be done in an open fire of cinders or small coke, not too hot. Heat the plates to a dull red heat in the dark, and leave to cool off. They require careful watching, or they will burn. .Some brass plates, after being rolled, annealed, and washed in sulphuric acid and water, have a red scale left on them. The scale can only be got rid of by grinding on a large stone, or otherwise by the use of pumice-stone and water, followed by dressing off with Tam-o'-Shanter stone. For cleaning up after firing, try a solution of about 1 part of nitric acid in 6 parts of water, slightly heating the biwss before plunging it in, leaving for a minute or two, then brushing with a stiff worn-out brush, and finally washing in clean water and drying in hot sawdust. The solution may be bottled and used over again, adding a little fresh acid from time to time.