Hi,

I think I have tried all of the methods mentioned (they all work) and many that don't. One easy method is to plug up the openings of the motor with blu-tac and spray with oven cleaning foam. Ensure a good covering and let it sit overnight then scrub with an old tooth brush. You may have to repeat a couple of times but this will improve the appearance markedly.

I still find the crock pot and glycol method the most effective but the oven cleaner works in most cases and is easier

Cheers,

Colin