saw this on a rc forum..their comments below.
I'm familiar with cleaning a well used brushed motor by running at low voltage in distilled water. You'd be surprised at how much gunk comes out -
Depending on the size of the motor hook it up to 1 or 2 d cell batteries and run it in a glass of distilled water (not that it would make much difference). You will notice a huge difference compared to stock motor. I did it to a speed 300 motor in my mini t and couldn't believe the difference it made. It has to be done right from the start though. Look it up for a more detailed explanation and for how long you should do it for.
