There is science in cleansing obstinately dirty bottles, jars, mortars, and other apparatus used in the car-bonator's laboratory. Before cleansing an implement, the first thing to consider is whether the vial or article about to be washed is worth the material which has to be wasted upon it. If not, then throw it away.

On any article use water first and next soap. Soap is incompatible with a great many chemicals employed in a bottling shop, and in some cases had better be left out altogether. Water will dissolve out most mixtures with which soap is incompatible, even if they are incorporated with oily substances. Persons dash soapsuds right into a graduate that has contained tinctures or solutions, and then find it more difficult to wash out than before, while if they had used water alone it would have been cleansed.

Powdered pumice stone, marble dust, sawdust, sand, brick, shot, emery, wire and paper, solutions of soap in diluted alcohol, and of caustic potash, soda, acids, etc., are sometimes used, and where applicable no doubt answer the purpose. But no single one can be recommended for a good all-round cleanser. Powdered pumice stone is an excellent thing for scouring mortars and brightening spatulas or any cutlery. It is also useful when introduced into large glass bottles or jars (such as are used for keeping extracts, essential oils, etc.) on paper, and a bent wire employed for scouring. Dry sawdust is good for removing grease from mortars and spatulas.

An efficient method for cleansing graduates, tubes, burettes, pipettes, etc., is to fill them with a rather concentrated solution of permanganate of potassium, which is allowed to remain in it for several days. The vessel is then rinsed with diluted hydrochloric (muriatic) acid and water. In some cases it will be found best to use a strongly alkaline solution of permanganate of potassium. This is particularly the case when a glass vessel has contained solutions of a vegetable constituent, containing oily or waxy matters, extracted by volatile solvents.