Skin Bleaching and Whitening Tips from Country Life in America, "Beauty from Milady's Garden", 1915

Cucumbers may be made into all manner of healing things for the skin, and are also an effective bleach ...

Oil of sweet almonds - 4 ounces
Fresh cucumber juice - 10 ounce
Essence of cucumbers - 3 ounces
White castile soap (powdered - 1/2 ounce
Tincture of benzoin - 2/3 dram [Ed: it might also say 3/4 dram - the text is very hard to read.]

The juice of cucumbers is obtained by boiling them in very little water. Slice them very thin, skin and all, and let them cook slowly till soft and mushy. Strain through a fine sieve and then through a cloth. Make the essence by putting an ounce and a half of the juice into the same quantity of high-proof alcohol. Put the essence with the soap in a large jar or bottle -- the larger the better -- as the mixture requires much shaking. After a few hours when the soap is dissolved, add the cucumber juice; shake till thoroughly mixed, the pour out into an earthen bowl and add the oil and benzoin, stirring constantly until you have a creamy liquid. 

(...)

Lettuce cream may be made in the same manner, merely substituting the lettuce and orris for the cucumber juice. The lettuce should be scalded in boiling water, let stand a few moments, then remove and pound the lettuce in a mortar; strain through a cheesecloth.