Curious- and maybe I missed it in the thread- have you attempted cleaning again with anything yet? I feel that cleaning cymbals neither ruins nor improves the sound, it just changes it. If I were playing bop or something else that needed smoky, dark-sounding cymbals, I'd get K's, HH's, or equivalent, and never clean them. I'd do the same even with A's, AA's, etc. if they were only for studio work. With the pop/rock/r&b stuff I typically play live, I use A's, AA's, or equivalent, and I choose the cymbals that sound like I need them to sound when they're new- no need to wait for them to mellow- so I keep them cleaned. It also makes them look better under stage lights, which is a good touch for showmanship & presentation. My cymbals are regular finish B20's- if I used any with a brilliant finish, I'd just clean off fingerprints with glass cleaner.
To your questions in the OP: I used Brasso on the marching cymbals back in high school, with mediocre results. It cleaned some, but not well, and kinda turned the cymbals' color. (Maybe it was residue I didn't completely remove...?) I've used Buckaroo some; highly effective, but messy, and it's a long, two-part process. You pick off a wad from the larger, what smells like light kerosene-soaked wooly wad in the container, and rub it (with the grooves, not against), and it creates a black smudge-y residue on the cymbal. I presume this is the grime that it's removing. (I recommend wearing black sweatpants, a shirt you don't care about, and hold the cymbal in your lap.) You can do a section, or the entire side of the cymbal. Then, you use a black towel or otherwise rags you don't care about, and buff off the black residue. Works very well, but will make your hands/fingers sore from all the buffing, and the black residue that will inevitably end up on your fingers won't wash off for a couple of days. The smell will linger in the room for a day or two.
I've had equal results with faster and less messy effort & process with Zims / Groove Juice. I put the cymbal in the bathtub, spray it generously with the cleaner, leaving no part of the up-facing side uncovered (if it's bell-up, start in the middle and move in a circular motion outward; bell-down, do the opposite). The instructions say to let it sit for a minute or two and then rinse it off; I scrub the cymbal lightly but thoroughly with a nylon-bristle bathtub brush in the same circular motion first. Then, rinse the cymbal. If I've let it go for a while and they're really dirty, I repeat it once or twice. I dry them with a regular towel and place them straight back in the cymbal bag. They don't end up brand-new looking, but close. Logos are gone, of course, but it doesn't matter to me, I'm gonna use them until they begin to crack, and I'm not hard on cymbals. I've had most of mine for a couple of decades.