This section is from the book "The Boy Mechanic Vol. 2 1000 Things for Boys to Do", by Popular Mechanics Co.. Also available from Amazon: The Boy Mechanic, Vol2: 1000 Things for Boys to Do.
Articles of brass, copper and bronze may be given a bright luster by dipping them into a solution composed of 50 oz. of nitric acid, 25 oz. of sulphuric acid, liquid measure, and 1/2 oz. of soot and 1/2 oz. of salt, by weight. After the articles are dipped into the solution they are removed and thoroughly washed, then dried in sawdust to prevent streaks.