Watch this science video tutorial from Nurd Rage on how to dissolve glass with drain cleaner. They show you how to dissolve that glass with sodium hydroxide (drain cleaner).
Glass is nearly invulnerable to chemicals and thus why it's the preferred material for chemical containers and reaction vessels. But when exposed to molten sodium hydroxide even glass will dissolve.
To perform the reaction a steel container is used as it's resistant to the sodium hydroxide.