What is your cleaning regimen? I scanned the entire thread and you've mentioned using a Knosti with 91% alcohol as the start. What comes next? If I can improve my cleaning I'm always looking for tips.
No real regimen, I've found records that look perfect but play noisy can have all sorts of weird crap in the groove, I've not found any approach that works quickly for all of them.
My first step is using carbon fiber brushes misted with 2-3 pumps of distilled water from a good atomizer. This collects anything loose. Then I take a listen to the record and for a large number of them, I'm done, I don't need to go any further.
If a record demonstrates surface noise that would be indicative of crap stuck in the groove, it is onto the Knosti with 91% alcohol. The record is removed and the excess alcohol shaken off, then placed in the drying rack (the 91% alcohol means the record is going to be dry in 2-3 minutes).
Now listen again. Depending on what I hear, further attacks typically involve velvet pads soaked with alcohol before playing the album. This further softens the remaining crap in the groove and gives the stylus a shot at raking it out. After playing the album I'll use another misted carbon fiber brush to pickup anything now on the surface of the vinyl. Mind you, this last step is for the records everyone else will give up on. I have original pressings of records that were GIVEN to me because of "obvious groove damage." Most of them came clean with repeated soaking/playing cycles. A very few unfortunately do demonstrate damage from a damaged/worn stylus. I'd say the ratio is 8:2.
But I'm mostly in agreement with Roy Gandy, I don't think records need cleaning beyond being played.
In fact I've concluded that there is a bit of a record cleaning paradox: If you want to make a record dirty, just clean it.
Obviously most of you guys are controlling the amount of detergents used and working diligently to rinse it off records, but there are plenty of misguided people out there using high concentrations of dish soap and failing to sufficiently rinse. And that is if we're lucky, some people are still using those record cleaning cloths that are impregnated with something (silicone?) and squishing anything on the surface into the groove, adding some silicone and fibers from the cloth for good measure. A few more plays and cleanings using that regimen is going to make for a record that is very challenging to clean later on.
I wish I had a fast approach, but I'm happy to have an approach that at least yields quiet records with no more residue in the groove, no catalyst to start a new round of surface noise.