Who has painted their engine with a spray gun?

I can't chime in with spray-gun experience but how the heck do you guys with cars that get driven a lot keep your engines so damn clean? I've put about 10k miles on my current 360 and most of the front of the engine is covered in a layer of rubbery oily grime. Granted it leaks oil from between the intake and front china rail but I can't see how that could get thrown over the entire front of the engine. It almost seems like rubber from the v-belts, maybe my belt alignment is off? Belts are still in great shape though and never get thrown even when revving to 6k RPM.
The trick is to clean often, don't let the grim build up. Some of the dirt or grease could be coming from the roadway and not just from an oil leak.