Rottenstone is a polishing abrasive usually made up of various forms of silica and weathered limestone. As I sought a good method to clean glass plates prior to making ambrotypes, I tried applying rottenstone with some water and grain alcohol to their surfaces but ended up finding simpler methods to clean the glass. One day I looked at the bottle containing traces of the solution and noticed the streaks the rottenstone left on the side of the bottle after the water and alcohol had settled to the bottom. These images are the result of pouring a bit of the rottenstone solution onto plates of glass and hitting it with a few bursts of compressed air to see what happens.