White Wax: Beeswax Bleached in Ribbons by Sun, Air and Dew, Ure 1839

Yellow beeswax turns white in the sun. Ure (1839) describes the old method: melt the wax, run it into thin ribbons on a wooden roller turning in cold water, and lay the ribbons out on canvas in the open, turned and watered, remelting and re-ribboning until no yellow is left. Chlorine cannot be used: it makes the wax brittle. The picture: a wax bleachery at Albi, France, with the wax spread on canvas frames above the grass (BnF, Wikimedia Commons, public domain).