Don't ingest it. Would cause problems if it gets into your stomach lining. Here is a guy smashing a Thorium glass Takumar with a sledge hammer, and a cloud of smashed glass going everywhere. I remembered the words of my Physics teacher when watching this.
I use a UV lamp, left over from an old optics lab. Does the trick, and does not dry out the lubricants as happens with sunlight. UV/c band will not work, as per reading about others trying it. I suspect the light in that band does not penetrate deep enough into the glass.