I stumbled upon this interesting tidbit while reading The American Frugal Housewife ©1835. Personally, I've never heard of this before and found it fascinating. Their are two examples below, one is for carpet fibers and the other for material for clothing.
When a carpet is faded, I have been told that it may bo restored, in a great measure, (provided there be no grease in it,) by being dipped into strong salt and water. 1 never tried this; but 1 know that silk pocket handkerchiefs, and deep blue factory cotton will not fade, if dipped "in salt and water while new.
An ox's gall will set any color,—silk, cotton, or woollen. I have seen the colors of calico, which faded at one washing, fixed by it. Where one lives near a slaughterhouse, it is worth while to buy cheap, fading goods, and set them in this way. The gall can be bought for a few cents. Get out all the liquid, and cork it up in a large phial. One large spoonful of this in a gallon of warm water is sufficient. This is likewise excellent for takfng out spots from bombazine, bombazet, &jc. After being washed in this, they look about as well' as when new. It must be thoroughly stirred into the water, and not put upon the cloth* It is used without soap. After being washed in this, cloth which you want to clean should be washed in warm suds, without using soap.