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 ...

To Conduct Demonstration 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 ...