Congrats. The crud is a little oil residue, fuel mix from the cyl on shut down, and dirt getting past the air filter system. All dries every time you shut off the engine after a road trip. The build up is always greater if there is more of the crap entering the intake system from poor connections, blow buy, and the oil separators failing. The back side of the valve is where it all collects.

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2005 X5 4.8IS
The Blue ones are always FASTER....

Current Garage:
2005 X5 4.8is
2002 M5 TiSilver
2003 525iT
1998 528i
Former Garage Stable Highlights
2004 325XiT Sport
1973 De Tomaso Pantera, L Model
1970 Dodge Challenger T/A 4 sp Alpine White
1970 Dodge Challenger T/A 4 sp GoManGo Green
1971 Dart Sport, “Dart Light” package
1969 Road Runner 383
1968 Ply Barracuda 340S FB Sea-foam Green