I will add that cleaning older records is very difficult because of several factors, including the fact that, according to a paper I read published by SHURE, the stylus running at 33-1/3 rpm’s contacts two microscopically small points on the groove walls. The pressure on these points of contact is approx. 26 tons per square inch. The implications of this are obvious for stylus wear. However, I believe (no proof yet) this same pressure, and the heat of friction on the groove walls, also momentarily softens the vinyl and causes debris to stick to the groove walls. Normal cleaning methods have a tough time removing that debris.
Also, this same article talks about the effect on the stylus causing wear "flats" that act like chisels that fracture the vinyl wall. The wave crests created by this condition also contributes to a worsening of the reproduction, but my opinion is that the tiny shattered vinyl bits get stuck in the bottom of the grooves where they are very difficult to remove with micro-fiber pads. Perhaps this is why playing a record shortly after cleaning dredges out the stubborn stuff. I used a very fine-tipped, and inexpensive, conical stylus for my "play-cleaning".
The paper was originally published in 1954 when cartridges ran at higher weights and styli were not as good as we now enjoy but, many older records could be very hard to clean because of the playing that they saw early in their life.
Too much information perhaps, but I find this stuff very interesting....