I had a set of Bones Swiss that had gotten really gummed up due to putting totally wrong kind of lubricant in them and leaving them outdoors. They are maybe 12 years old and not been used at all for a few years.
I figured I might as well try to salvage them, so I disassembled them completely and soaked them in mineral spirits. Didn’t work. Soaked them in acetone, came out perfectly clean. While putting them back together I was thinking about what it is that makes these special, I mean most bearings are metal balls in metal grooves, but I know the tolerances can be different, maybe the metal used is different as well? The cages shouldn’t affect much I assume. So I was thinking maybe whatever was special about the Swiss when new must have worn out over the years, but who knows. Any way, I put them back together, lubed them up with some pretty fluid stuff that came with some electric clippers and damn, they are really fast again. Noticeable difference to the Bones Reds I had.
Swiss are something else.