I would try polishing with cerium oxide polishing compound. This is what glass working shops and mirror plants use. Keep the glass wet with the polishing compound and take your time, it will work fine, put a torch on 1890s glass and it will probably explode. Amazon has cerium oxide powder.

I'm not an expert but I worked in the mirror industry as a chemist for a while. Cerium Oxide actually has a solvent effect on glass.