I cleaned mine in phases. First I sprayed it with engine degreaser and scrubbed it with a toilet brush. I let it sit for a while and then got out the high pressure sprayer and sprayed it off (careful to avoid intake and exhaust ports, i stuffed those with rags and tapped over them as well). Next I made a soda blaster and spend an hour or two blasting it (went through about 3 boxes of soda). Then I washed it again with HOT soapy water and toilet brush. Final inspection with a pick and towel. Before paint I used marine degreaser as a final cleaning.