I keep my fixer (at working dilution) in clear glass bottles. (I understand it's not particularly light-sensitive, and the online store was out of brown amber glass bottles at the time anyway.) My latest batch started getting some black precipitate on the bottom and some gray staining on the walls of the bottle, although the fixer was not yet exhausted. Judging from other posts I found once, I think these are small amounts of silver or some silver compound that is, for whatever reason, prematurely falling out of solution (is "falling out" the correct term?). Anyway, after dumping the fixer out, the black particles at the bottom are easily removed, but the sides of the bottle are still cloudy. (I have found I can "wipe" the walls clean, but the bottle has a narrow neck, and my finger is only so long.) I've tried filling the bottle with some hot soapy water, some diluted Windex, and some diluted Clorox bleach. The walls are still cloudy, and I'd like to know how to get them clean. I want to know if this is possible, since I'd like to be able to store a different chemical in the bottle after I clean it. So any advice would be appreciated, especially methods that use household cleaning supplies rather than specially photographic chemicals that I'd have to order. Thanks in advance.