An 18th century advertisement:
~ R E W's Unparalleled Diuretic Horse Balls prepared by no one in the Kingdon
but his Assign and Successor E J Palfrey ~
Answering every purpose where Physic is required [to be sold] by the Maker, E J Palfrey, Farrier, at the Horse Infirmary, Coventry, where DISEASES and ACCIDENTS incident to HORSES are judicious treated; Horses and Colts cut, Tails set, Ears Foxed or Cropped, Stars in the forehead made in the best and modern Manner &c &c.
The really terrifying thing about this advertisement (for which, to Rosemary Hall, many thanks) is that the Coventry Horse Infirmary might have been the best thing available.
It obviously served the needs of fashion as well as health: I can't think of any purpose cropping a horse's ears would serve other than fashion. Foxing appears to be much the same thing as cropping: Charles Augustus Goodrich's 1831 New Family Encyclopaedia, or Compendium of Universal Knowledge describes foxing thus:
"FOXING. This consists of depriving a horse of a portion of his ears, for the purpose of improving his looks. An easy mode of performing the operation is to take a small paintbrush and with paint in contrast in colour to the horse, mark the ears of the shape and length required: then place a switch on the horse's nose, at the same time holding up a fore foot; with a sharp knife cut the ears in the line made by the paint. Wash the wound with salt and water once a day for a week, after which apply sweet oil until healed. Those horses only which have small, thin, delicate heads, are improved by foxing."
Washing the wound afterwards, I would imagine, must have depended on whether the horse would let you anywhere near it after you'd shaved bits off its ears with no anaesthetic.
I have managed to track down an Elizabeth method (in fact, several) for making a star, but more about that tomorrow.