FreeParty
Member
I have been gifted several old glass one gallon carboys that are spherical. The problem is they have some old crusty residue inside that I cannot remove. I have tried sanitzer and a bottle brush. My second attempt, I boiled water and filled the carboys to let it soak and then tried cleaning it with a brush but no luck. I do not know what was in the glass before. How can I kill this residue organically and get to work?