Fused glass cabochons can get a scummy bottom from the fiber paper or shelf primer, and devitrification on the top. To clean these up, you can use wet and dry sandpaper or diamond pads, but an easy way is to tumble them with silicone carbide grit.
Thanks to Twylah for asking about this and inspiring me to make the video. Hope it answers all your questions.
The video tutorial includes the design, materials, and equipment information, as well as the cutting of glass, firing and slumping.Continue reading Tumbling Fused Glass Cabochons for Fire Polishing, Project Tutorial