Take putty powder and add to it sufficient sweet oil to make a paste. Rub with this the brass or copper until all foreign matter is removed. Then wash the article with soap and water and rub dry with a clean cloth. Brass may also be cleaned with lemon or orange juice thickened with whiting. Apply with a chamois skin or a flannel rag. To remove verdegris from brass, add to the juice of one lemon a teaspoonful of salt, mix well and apply with a soft flannel. Rinse and rub well with chamois skin. Be very careful if you have a scratch on your hand, as verdegris is a poison. Some collectors brighten brass without the use of paste, simply applying hot ammonia water. Or, better still, pour the aqua ammonia directly on the brass and scrub with a brush. Rinse in clear water and wipe dry. The result will be a beautiful polish.