I always thought mold was green, but in any case, I think an ultrasonic machine might help. I have a CleanerVinyl Ultrasonic RCM. About 10 years now, I think. I have about 1500 records and ALL have been through the RCM at least once. A handful have been very noisy and dirty - no mould though. After much experimentation, this seems to work for me - YMMV of course.
- 10 minutes in RCM at about 35C - vinyl melts at 100C or so, so no worry about hurting it. My reasoning is I clean my dishes in warm water, so why not vinyl?
- Disc doctor - scrub about 3-4" section of vinyl about 20 times - and I mean scrub - find a good solid surface, put a towel on it, then the wet record and scrub and press down HARD - move around the vinyl doing this - both sides if it needs it, otherwise, just the offending section. Scrubbing won't hurt it assuming you are using the DD brushes.
- rinse under tap water, be careful of the label
- RCM for 10 minutes again and scrub and rinse and RCM for 10 again
- dry
this process works for the very dirty onesI had - maybe a dozen or so. I have had one used one that I could not get clean, so it went back to the seller on Discogs. I guess I could have repeated the above process, but there was no discernible difference to my ears after the above process, so I gave it up.
I don't have a VPI, but you might want to try heating the water - just get hot water from a kettle and put it in the VPI. Might be worth it.
I was initially worried about the CleanerVinyl using a fan to dry the records, but I have had zero issues with my records. My room is a man-cave downstairs, and my dog does come down most days to chill with me, so there is dog hair, but so far, no issues.
Good luck!.