I just lay the record out on a towel, grab my diluted disc doctor solution bottle and a bowl of distilled or purified water (I've seen people argue which is best, but really I don't see much if any difference either way. I'm not that anal), and some paper towels.

Get the LP damp with the water and the rinse brush, squirt a few drops of solution on the scrub brush, scrub around with the grooves for a bit, usually woring in thirds and scrubbing a half dozen or so times on each third. Wipe the scrub brush with a paper towel, then use it to soak up the excess bubbles. On really dirty ones, it sometimes helps to let the solution soak in for a couple minutes.

Then, wet the rinse brush and do the same type of scrubbing you di with solution with distilled water. Make sure you use plenty of water and don't stop until you get absolutely no bubbling on the record surface.

Then, just wipe quickly with a clean paper towel and dry the rest of the way in a dish rack.

That generally takes care of everything. I have had occasional grease spots and such that took a second cleaning. Then, I go ahead and use the solution full strength instead of the normal 2 to 1 mix of solution and water I generally use. One good tip I got was to stick a nickel in the gap near the brush on one of your brushes so you always know which one is your scrub and which one is your rinse brush.

Sounds to me like those records have groove damage, usually coming from getting played with a worn stylus. Those Ray Charles records I mentioned look flawless, but play like crap, sounds like what you've got. If so, nothing you can do outside of software that filters stuff out, which has a nasty tendency to mess up the sound when used heavily enough to do much on realy noisy records. I use a stand alone CD recorder for vinyl, and you can then transfer the files to your computer to filter as much as you want. I do so when the record is just otherwise hopeless. My soundtrack of Easy Rider was way trashed and this helped it become at least listenable.