Indeed

This is a mug I made 25 years ago when I was experienting with using soda salt to replicate traditionanal salt glazing - without the polluting Chlorine gas coming out of the chimney. For those unfamiliar with this old European invented technology; pots and other ceramic ware (like drainage pipes) are fired to the required temperature (1000 -1300 deg C) and common salt is thrown into the firebox. The intense heat splits the molecular bond of sodium and chlorine. The sodium makes a glaze with the silica in the clay and the chlorine escapes up the chimney. Sounds like an invironmentally dangerous thing to do. And it is, but actually on the small scale of a studio pottery the chlorine quickly oxidises and returns as acidic steam and safely falls to earth. Iron roofing cops it and rots out faster than usual. So soda has been used now these days and the exhaust gas is mainly harmless water.