Google “pure” and you will get 240 million hits, featuring the word in all of definitions. In the main these hits, I am sure, use the word pure in one of the following contexts: homogeneous; free from impurities; containing nothing extraneous; utter; faultless; chaste and so on and so forth
Far less common is the use of pure in one of its older meanings, one that seems to have fallen into disuse in the 20th Century: pure was used as a noun meaning dog dung. Dog dung was used in the tanning industry and apparently got its name for its cleansing properties.
19th Century social commentator Henry Mayhew had this to say pure and pure finders in his book “London Labour and the London Poor” (I found the online text here).
"The pure finders meet with a ready market for all the dogs'-dung they are able to collect, at the numerous tanyards in Bermondsey, where they sell it by the stable bucket full, and get from 8d. to 10d. per bucket, and sometimes from 1s. to 1s.2d. for it, according to its quality. The 'dry limy–looking sort' fetches the highest price at some yards as it is found to possess more of the alkaline or purifying properties; but others are found to prefer the dark moist quality. Strange as it may appear, the preference for a particular kind has suggested to the finders of Pure the idea of adulterating it to a very considerable extent; this is effected by means of mortar broken away from old walls, and mixed up with the whole mass, which it closely resembles……
...The pure collected is used by leather-dressers and tanners, and more especially by those engaged in the manufacture of morocco and kid leather from the skins of old and young goats…. In the manufacture of moroccos and roans the pure is rubbed by the hands of the workman into the skin he is dressing. This is done to 'purify' the leather, I was told by an intelligent leatherdresser, and from that term the word 'pure' has originated. The dung has astringent as well as highly alkaline, or, to use the expression of my informant, 'scouring,' qualities. When the pure has been rubbed into the flesh and grain of the skin (the 'flesh' being originally the interior, and the 'grain' the exterior part of the cuticle), and the skin, thus purified, has been hung up to be dried, the dung removes, as it were, all such moisture as, if allowed to remain, would tend to make the leather unsound or imperfectly dressed.
The number of pure-finders I heard estimated, by a man well acquainted with the tanning and other departments of the leather trade, at from 200 to 250. The finders, I was informed by the same person, collected about a pail-full a day, clearing 6s. a week in the summer -- 1s. and 1s. 2d. being the charge for a pail-full; in the short days of winter, however, and in bad weather, they could not collect five pail-fulls in a week."
A grim way to make a living in grim times… Still, it doesn’t stop the not wife and myself having a good laugh when we see businesses like Pure Tanning. I hope to God they have sunbeds!