When ammonia levels were determined to be safe ... fruit cocktails and 4 ounce plastic bowls, according to its website. The cannery in Oroville was originally Hearst Canning in early 1900s.

If necessary, protect non-glass surfaces of an overhead projector with clear plastic. Dip one Q-tip into concentrated hydrochloric acid (HCl) and a second cotton swab into concentrated aqueous ammonia ...