I've been cleaning some particularly stubborn glorp stains off items of my lab glassware, stuff thats refusing to fuck off. Just been preparing a chromic acid bath. Made with concentrated (98%) sulfuric acid, to make a saturated solution of dichromate, in this case sodium dichromate, in the concentrated sulfuric
Its a somewhat safer to handle alternative to piranha acid (peroxymonosulfuric acid, made with concentrate H2SO4 and hydrogen peroxide, its dangerous stuff, very, very dangerous, but it WILL remove even the worst stains if they are, or ever have been organic in nature. Piranha bath will rip apart inorganic graphitic carbon, oxidizing it to CO2.
Really nasty shit. Chromic acid is an alternative, not the tendency to cause things to explode violently. It has another set of pros and cons. Not quite as powerful and deadly a cleaning mixture as piranha acid, and both chromic acid bath and the liquid left behind after the batch of chromic acid has spent it's oxidizing power are both Cr (VI), and hexavalent chromium is highly toxic, carcinogenic, generally unpleasant stuff and rotten for the environment. I don't throw it away though, its still saturated with chromium salts, which can be recovered and recycled and used for other things; waste not, want not.
