rottenstone

The sides were painted a rich brownish-red, which was lovingly hand-polished to a shiny gloss with oil and rottenstone.

I was kneeling on the other side of it, polishing the lock with an oily rag and rottenstone.

Tripoli and rottenstone are light, porous, siliceous rocks which have resulted from the leaching of calcareous materials from various siliceous limestones or calcareous cherts in the process of weathering.

The smoothing is done with a lead lap and fine emery, and the polishing may be accomplished by means of a lead lap, whose surface is hacked and supplied with rottenstone and water.

Bath brick or rottenstone may be used for polishing.