Iridescent glass

I do not know the formula. In principle it is a thin deposit of metal,

It can be removed by sandblasting, etching or abrasive tools.

-lauri

different manufacturers use different chemicals. a bunch of them use tin chloride fumed on when the glass is coming out of the rollers and still hot.

Since I have it about, what sayest thou to brushing on etching paste, aka hydroflouric acid?

It should work but Be extremely carefull, read the safert notesand MSDS first. It is dangerous stuff. As always test on a scrap first

-lauri

The irid surface can easily and safely be removed with sandblasting or etching cream. If you want, you can return a full smooth gloss to the etched parts by fire polishing in a kiln. Pieces done that way can look delicately elegant.

HFC is truly horrific stuff but the amount contained in Etching Creme is too little to be of serious concern. It's commonly used by thousands of hobbyists.

For anyone considering using HFC, here's an article explaining why they should reconsider.

The irid surface can easily and safely be removed with sandblasting or etching cream. If you want, you can return a full smooth gloss to the etched parts by fire polishing in a kiln. Pieces done that way can look delicately elegant.

Thank you! That is very good to know!