When you need to remove trash or a bubble in the cloisonne enamel jewel, use a diamond bur. And save this bur for only your cloisonne and enamel jewelry repair. A good quality bur, as the diamonds are smaller and spaced close together. If they are large a spaced out too much it will rip the enamel instead of a fine sanding.
One of the most important things is to glass brush the sanded area, be sure it is dry and fire. This way there is no shadow of the cloisonne enamel jewelry repair work. And now you can apply more enamels to level the repair of the jewel.
There is more detail on this under https://alohilanidesigns.com/topics/repairing-cloisonne-enamel-jewelry/
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