Coleman recommends 409 cleaner. Do not use Simple Green.
I cut the bristles short on a throw away paint brush. I put an old shower curtain on the carpet and put towels around the edges. Spray, brush rinse.
You might want to tighten the four clamp bolts a turn or so the compress the gasket a little. You don't want to over tighten. Just a single turn should do it.
I just had to replace my motors and I was surprised how dirty the squirrel cage fan was.
Covered in mildew. Hard to get to without taking the motor out.