Take an ounce of oxalic acid, dissolve it in a pint of soft water,
and keep it in a bottle well corked; dip a soft sponge into the
mixture to clean the tops with, and if there are any spots which
refuse to disappear, rub them with a little fine Bath brick dust:
sponge the tops afterwards with clean water. Take particular care
always to have any mixtures, or powders for boot-tops, labelled with
the word poison in large letters, as fatal accidents have arisen from
oxalic acid, being so like Epsom salts in appearance, as to be often
taken for them in mistake.