As I posted in another thread, I acquired a couple food grade blue barrels for my maple syrup operation. These had been used to ship butter, so you can imagine how hard to clean they were. I filled them approx 2/3 full with soap and water, and they laid in my yard for five weeks.....every day I would roll them around, and flip them end-for-end. This past weekend I drained the soapy water, and to my knowledge they hadn't leaked at all. They would swell on hot days, and contract on cooler mornings, but the bungs, which were sealed only with the rubber gasket, never leaked.
