You clean it with Dielectric Cleaner, you can get it at most automotive stores like Advance Auto, I've also heard of an old trick using a pencil eraser to clean the surfaces.
I had a problem with my a/c fan. I took out the glove box and accessed the ac blower motor(on the passanger side). unbolt and remove. take a look at the motor brushes they may be covered in black. take the motor apart and clean brushes and contacts. Put everything back and it may work. It worked for me.
Motor brushes ride one the commutator.
check the brushes and bearings in your motor make sure you have a good ground and the connections are clean but most likely the motor is shot
Carbon
I had a problem with my a/c fan. I took out the glove box and accessed the ac blower motor(on the passanger side). unbolt and remove. take a look at the motor brushes they may be covered in black. take the motor apart and clean brushes and contacts. Put everything back and it may work. It worked for me.
The normal number of brushes is 2.
Carbon is much stronger and because the motor commuter is spinning copper brushes will wear off quickly.
the reason for brushes is to makethe motor revolve. The more brushes probably make a more powerful starter motor
Test Tube brushes are used to easily clean the test tubes .When you've been using latex paint
chimney brushes of course!
With a set of chimney sweep brushes.
I would clean the grease off of the commutator and brushes and put a 3/4" drywall screw through the thermal switch. All of these things are inside the motor. there is no need to remove the motor or regulator. Instead, remove the end cap ( where it plugs in) and pull out the guts of the motor ( end cap, brushes, springs and armature). Note the rotational position of the armature where it comes out of the motor easily. After repair, preassemble the guts ( paying attention to the rotational position of the armature) and reinstall into the motor.