I wanted to give an update.
I 'broke-i'" a MOAMB3 the way I personally think it should be done (by just running it at low voltage for long periods of time). Once the break-in was done (roughly 12 hours at 3.3v), I made sure the grooves were worn out of the brushes, and hooked it up to 12 volts. It turned 81.5k RPM.
I am frequently asked how to run in MOAM motors, so I wanted to post here and explain my personal theory on it. I will either put the motors in a car new, and just run them when I'm at the track for practice, or I will run them at low voltage for a period of time. I don't like the idea of putting my motors in water, or any harsh chemicals. I feel it is best to just let the brushes naturally wear in, and go from there. If I put a motor in a car to break-in, I will run it for a while (not letting it ever get too hot), and you will just know by feel when that motor is at its prime. Then I will take it out of the car and set it aside for a race.
My team uses a variety of chemicals to submerge the motor and break it in, but my problem with this is that it will strip away some of the plating on the outside of the brushes, which is where most of the electricity is conducted. That said, their broken-in motors break that 80,000 RPM barrier too, so I could be 100% wrong about some of my theory on it.
Everyone has their own method, but the point of break-in is to get rid of the groove in the middle of the brush. In the future I plan to have the motors manufactured with flat/already broken-in brushes. One thing at a time though.