I couldn't resist sharing this, extracted from 'Workshop Hints and Helps' from a book by Donald De Carle.
"To clean mercury: Place a 10% solution of nitric acid in an iron ladle and pour in the mercury. Bring the acid to the boil and allow to cool. Dirt and grease will rise to the top leaving the clean mercury in the ladle bowl. Care must be taken not to boil the mercury as the fumes then given off are dangerous..."
The next hint tells you how to re-sharpen files: "Cover the files with water and slowly add sulphuric acid until a solution about 25% acid is obtained. It is essential that the acid is added slowly as considerable heat is generated which expedites the action, but it may also cause a violent eruption if the acid is poured in quickly in bulk."
There are many more like these, involving the likes of caustic soda, ammonia, hydrochloric acid, zinc chloride, oxalic acid, pure white arsenic and potassium cyanide (helpfully described as "very poisonous"). The interesting point is that this book was published in 1965, less than a decade before the Health and Safety at Work etc Act came into force. And not before time!
