Find a commercial cleaners (carpets/homes/dry cleaner) that offers detailing services. I have a local shop that does engine steam cleaning. For $40 the engine bay came out like new. Not the goop coating on black parts, but sparkling clean metal and plastic.

There is another car wash the next city over that puts the car up on a lift so they can get under to spray the grime off, then wash down in the engine bay. Great for long time oil leakage.

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clay

2002 s430 - Victor, a Stately & well tailored chap
1974 450sl - Frosch - Two tone green
1986 SDL - Polei

retired models-
1976 300D - Blei Vanst - it looks silvery
1972 220D - Gump - She was green, simple and ran
1995 E300D - Gave her life to save me against a Dame in a SUV
POS 1987 SDL - Beware Nigerian Scammers