TimpanogosSlim
Well-Known Member
Every once in a while we come across a deal on a glass carboy that can't be passed up. Often bearing a label warning of chemical contents.
I intend this thread to become a repository of information on how to clean them so as to be certain you aren't poisoning yourself.
A good friend of mine is a chemistry professor and former EPA site inspector and cleanup tech. He was slightly alarmed when i mentioned to him that I had acquired carboys bearing Nitric Acid labels.
Industrial grade nitric acid, he says, often contains traces of mercury salts. This is because mercury is used in the manufacturing process for nitric acid that does not have to be food-grade, because it lowers the amount of heat you have to put into the reaction by a large margin.
Most of that mercury is drawn back out at the end of the process, but some remains, and it sticks to the glass.
He said that if someone had been using them as fermenters for years, they are probably fine by now, but not knowing their exact history (though at least one of them also had a sticker marking it as having contained peach wine), here is the cleaning procedure he recommended:
Nitric Acid carboys:
Mix 1 gallon of ammonia+surfectant solution (Buy jug of ammonia-based cleaner at hardware store or janitorial supply, follow directions on jug) - swish around in carboy for a few minutes. This will stink, do it outside. The ammonia will draw metals off of the surface of the glass.
Then add 20 grams of EDTA Disodium (not EDTA disodium-calcium), swish around for some more minutes. EDTA is a chelating agent - it will bind the metals in the solution and prevent them from settling back onto the glass.
Then dump. This should be safe in the sewer system or wherever. Ammonia and surfectants won't hurt anything. Any free EDTA will rapidly acquire metal ions and neutralize itself. We're not talking about much mercury, and the mercury you're dumping is bound to the EDTA and can't do much harm anymore - it's just that when you know you have an option to avoid consuming mercury, you oughta take it. My guess is that this mixture won't even kill the grass but i haven't tried that. I plan to dump it on my concrete driveway and then eventually rinse with the hose.
You can get Disodium EDTA from purebulk.com - about $8 for 250 grams. The ammonia + edta solution is good for cleaning metals out of just about anything, also for removing oxidation from metals without harming good metal. If you can only get tetrasodium edta, use 40 grams. If you can get edta free acid, you could use 5 grams, but you can't get edta free acid.
This cleaning method may be recommended for carboys that have held other industrial acids.
Phenol carboys:
My new 6.5g carboy held a liquid phenol solution in the 70's.
Does it smell like phenol? If so, wash with water and detergent until it doesn't smell like phenol. If you have ever had electronics burn up, you have smelled phenol.
Does it smell clean? Good, it's clean, use it. No contamination concerns.
I intend this thread to become a repository of information on how to clean them so as to be certain you aren't poisoning yourself.
A good friend of mine is a chemistry professor and former EPA site inspector and cleanup tech. He was slightly alarmed when i mentioned to him that I had acquired carboys bearing Nitric Acid labels.
Industrial grade nitric acid, he says, often contains traces of mercury salts. This is because mercury is used in the manufacturing process for nitric acid that does not have to be food-grade, because it lowers the amount of heat you have to put into the reaction by a large margin.
Most of that mercury is drawn back out at the end of the process, but some remains, and it sticks to the glass.
He said that if someone had been using them as fermenters for years, they are probably fine by now, but not knowing their exact history (though at least one of them also had a sticker marking it as having contained peach wine), here is the cleaning procedure he recommended:
Nitric Acid carboys:
Mix 1 gallon of ammonia+surfectant solution (Buy jug of ammonia-based cleaner at hardware store or janitorial supply, follow directions on jug) - swish around in carboy for a few minutes. This will stink, do it outside. The ammonia will draw metals off of the surface of the glass.
Then add 20 grams of EDTA Disodium (not EDTA disodium-calcium), swish around for some more minutes. EDTA is a chelating agent - it will bind the metals in the solution and prevent them from settling back onto the glass.
Then dump. This should be safe in the sewer system or wherever. Ammonia and surfectants won't hurt anything. Any free EDTA will rapidly acquire metal ions and neutralize itself. We're not talking about much mercury, and the mercury you're dumping is bound to the EDTA and can't do much harm anymore - it's just that when you know you have an option to avoid consuming mercury, you oughta take it. My guess is that this mixture won't even kill the grass but i haven't tried that. I plan to dump it on my concrete driveway and then eventually rinse with the hose.
You can get Disodium EDTA from purebulk.com - about $8 for 250 grams. The ammonia + edta solution is good for cleaning metals out of just about anything, also for removing oxidation from metals without harming good metal. If you can only get tetrasodium edta, use 40 grams. If you can get edta free acid, you could use 5 grams, but you can't get edta free acid.
This cleaning method may be recommended for carboys that have held other industrial acids.
Phenol carboys:
My new 6.5g carboy held a liquid phenol solution in the 70's.
Does it smell like phenol? If so, wash with water and detergent until it doesn't smell like phenol. If you have ever had electronics burn up, you have smelled phenol.
Does it smell clean? Good, it's clean, use it. No contamination concerns.
