I spray mine off at the car wash with the high pressure spayer. If it's really dirty I'd think that on a cool engine carb cleaner would clean anything. Brake cleaner might be safer. Or spray with a mulitpurpose cleaner like Simple Green and then high pressure wash/rinse. Then just take your time and do some cleaning with a rag. See mine at www.msnusers.com/jimsdogtruckphotos