Dear Friends, In the Spirit of Spring, I have cleaned and reearranged the darkroom. This is roughly akin to my late mother moving the piano around the house every April, though the piano generally was not coated with dried fixer. Just dried tears <snip> Unk: We in the microbiology trade frequently and historically wrestle (sp?) with this same problem in our waterbaths. I have no Jobo and am not familiar with it's capabilities and this probably won't work for material purposes, but.... We turn up the thermostat to 110C once a week on Fridays and boil the contents for 15-20 minutes, returning it to normal and letting the bath cool overnight. These baths are, however, stainless steel and made for this kind of abuse. Keeps the water clean though (you can run off a dozen or so boiled eggs for breakfast at the same time). JB