This section is from the book "A Treatise On Beverages or The Complete Practical Bottler", by Charles Herman Sulz. Also available from Amazon: A Treatise On Beverages.
Leaden shot are very extensively employed for cleansing bottles. It is a convenient mechanical method in some respects, for lead is very soft as compared with glass, and owing to its high specific gravity, it exerts more pressure and greater friction; then, too, it is easily obtained in all sizes. But unfortunately lead is smeary and extremely poisonous. When bottles are washed daily with shot a film of black lead will sometimes be formed. This is easily removed with dilute nitric acid (free from sulphuric acid). In soda and beer bottles this film cannot be seen, on account of the colored glass; but occasionally a shot can be seen that has become wedged in at the bottom of the bottle, and held there, and thus contaminating the liquid by the chemical action of the beverage on the lead. And again, shot that has been thrown into a greasy bottle becomes coated with fat, and is unfit for further use, as it will only dirty the next bottle it is thrown into. The shot itself, when once clogged in this fashion, had better be cast aside. For these reasons shot for washing bottles is not to be recommended; and in our opinion the cleansing of glass bottles with shot should be absolutely prohibited where the bottles are intended for beverages.
Fir. 272. Foot Power Bottle Washer.
Iron shot is preferable to lead shot, as it does not affect the contents of the bottle. This shot has sharp edges, cleaning the bottle more thoroughly than lead shot.
This is a very economical and practical substitute for cleansing bottles, instead of leaden shot. It occurs native in masses and grains, and is extensively used in the arts for grinding and polishing metals, hard stones, and glass, and can be used alone as well as with diluted acids. It works much more rapidly than shot, on account of its sharp angles, and is in every way an economical substitute. Grains No. 5 or 6 are the most suitable for bottle-washing.