At least in my experience, this appears to be a common problem with VPI. I've had it happen with a number of bottles which have sat around, and I do mix the concentrate with distilled water. I don't know if any other cleaner designed for cleaning machine use either has the same problem, or is better. Maybe putting it in the refrigerator would help, but whether or not the mold is harmful for records, I bet even diluted the VPI concentrate isn't very good for anyone who mistakes it for drinking water.
VPI cleaning fluid and fungus
Does anyone know what the VPI cleaning fluid is made out of? I have a bottle that has been sitting for a few months, unused. I looked at it today and in the bottom there is a 2"X1" fuzzy grey-green ball that looks suspiciously like a huge ball of mold. Now, that can't be good for my vinyl. Granted, all of the fluid should be vacuumed off, but this still concerns me. Is this just a bad batch of cleaning fluid? Should I switch brands?