Sounds like hydrofluoric acid to me, which is even more dangerous. But seeing as you're making a vacuum chamber anyway, perhaps oxygen plasma could be substitut

Sounds like hydrofluoric acid to me, which is even more dangerous. But seeing as you're making a vacuum chamber anyway, perhaps oxygen plasma could be substituted. https://en.wikipedia.org/wiki/Plasma_cleaning https://en.wikipedia.org/wiki/Plasma_cleaning