do you clean stained water bottles?
by stain, I mean probably some kind of fungus that's entrenched on the bottom of the bottle. I've tried soap, scrubber, vinegar, even detergent, with decent results on one, but no luck on the other one ( and I scrubbed hard). I wonder if the stain is just residue that's latched onto the material, which is probably something close to low density PE, and not really harmful. I'm just curious to see if others clean theirs, re-purpose them or just toss them.