Again - not an expert.

I have seen tumbling in Cambay, Firozabad, Benares and Purdalpur, but that is not what you are after!

Putting color-colornats on a bead, then fire the beads in hope to achieve an effect?

Use a helmet, is what comes to mind first! The moment you "fire" your bead with a torch - mini or maxi - the bead will crack and fly in your face. A potentially dangerous task. The only way to avoid it would be to heat the bead up gradually (in a kiln), close to the point before it begins to lose it's shape - than the popping of the beads could be prevented.

None of this is really worth the effort, especially since you won't reach the desired aging effect anyway.