In Howard Priestman’s book, Principles of Woollen Spinning (1924), he discusses a variety of carding and opening processes. Included in these is a rag machine or
devil which is used to grind or pull rags of all kinds of knitted and woven wool fabric. The rags are beaten by a toothed swift and are literally shaken to pieces. In the book, he says:
The product of the devil is shoddy, mungo, or alpaca, as the case may be; shoddy being made from hosiery and other milled goods, mungo from milled cloth, and alpaca, or extract, from any class of material that has been carbonized.
He says that wool is
said to be carbonized when it is treated with sulphuric acid or other chemicals, in such a way as to destroy the undesirable vegetable matter and to leave the wool uninjured.
It would appear that a class of recycled woollen material was called
alpaca as compared to the wool from the Peruvian animal.
According to the OED, the name is made up of the Spanish (Arabic origin)
paco which is described as probably a Peruvian name. The word was originally
There is a 1604 citation from a history of the West Indies to
pacos, sheep bearing wool, then a 1753 citation to pacos as a species of camel, also known as the Indian sheep or Peruvian sheep. In 1827 another publication says
The paco or alpaco was first clearly described by M. Frederic Cuvier in 1821. Then in 1836 there is an advertisement for the Liverpool wool sales offering 400 bags of Alpaca wool, just landed.
Then the name seems to have been transferred to clothing made of alpaca, or of other thin wool resembling alpaca. There is no mention in the OED of any carbonization processed wools. The most recent citation in the OED is to 1900, to a woman wearing a
shabby, ink-stained alpaca dress. The name now is used only for the wool of the animal and signifying a luxury fibre.
Here’s a web page that talks about shoddy and mungo and mentions using alpaca noils as well as other noils in the manufacture of cheaper woollen goods: Wool Substitutes And Waste Products