Sleeved washers aren't designed to help prevent detuning. They help to make tuning smoother because they keep the tension rods from rubbing against the rim. In that regard, they do work. I use them and can notice a different when tuning.
Got some 14" Amedia Kommagene hi hats, 900/1100. The profile is fairly flat, which really helps darken the sound a lot. They're a good match for my 18" Old Stamp K.
The surface seems to be a bit brushed or burnished before the patina is added. They certainly feel like old cymbals.
I'm going to...
I used to have a 22" at about 2800 grams. It was a beautiful cymbal. It pretty much sounded like the most perfect vintage A Zildjian.
It had that AZ clarity, but without the annoying highs. Instead is had a low, dark, mellow wash with just a bit of growl.
I love those sticks. I love the feel of the reverse taper and the clicky cymbal sound.
I used to use the Regal Tip Session, which was Carlock's signature stick when he played Regal Tip. http://www.regaltip.com/products/drum-sticks/wood-series/session
I would try a Mr. Clean magic eraser. Since there are no liquids involved (other than water), you can be very precise with your cleaning.
Otherwise, rubbing alcohol may work. Just use a swab or something similar to keep it precise.