Ceresine Wax: Ozokerite Boiled with Sulphuric Acid, Then Bleached (Gregorius 1908)

Ceresine is the dark mineral wax ozokerite made white. Hot concentrated sulphuric acid burns out its colouring matter, then a bleaching powder and a filter press take it to yellow, and a second round to white. This follows the boiling method given in Rudolf Gregorius's Mineral Waxes (1908). Source: R. Gregorius, Mineral Waxes, their Preparation and Uses (1908), pp. 35–42. Bone black is the source's alternative to its usual bleaching powder; the equipment is ours. Picture drawn by Youblob.