TAKE the Blood of a Buck Hare, dilute it in an equal Quantity of the Urine of the Person for whom it is design'd, and filter through a Piece of Linen. Keep it in a convenient Vessel, and use it after the following Manner. "If you have a mind to get rid of your Freckles, you must stay in your Chamber for three Days; and when you go to Bed, wet them with a small Piece of Linen dipp'd in the above Water, and take care not to rub it off. The next Morning repeat the same Operation, and several times in the Day for three Days together. The fourth Day you must wash with Pimpernel Water, and may walk about your Business. You must use the Pimpernel Water four or five Days, during which Time the Freckles fall off like so many Scales, or like Meal-Dust, and the Skin will remain white, smooth, fresh and fair."
Freckles were not considered desirable for several centuries; various "remedies" can be found, ranging from the benign to the really harmful. This one may not be particularly harmful, but... yuck! Please don't go washing your face with rabbit blood and urine. (At least they said to use your own urine, and not someone else's...)
This receipt could only be followed by someone with enough leisure to stay in the house for three days; the "regular folks" would have too much to do and could not afford the luxury of time.
Source: Abdeker: Or, the Art of Preserving Beauty, 1756.