how to clean this?
 

Just spray compressed air with a PC duster?
http://www.mindspring.com/~houlihan/merc/banjo1.jpg
http://www.mindspring.com/~houlihan/merc/banjo3.jpg


banjo. (click here for the web page)

My Approach
 

I would unscrew the fitting. If the fitting is filled with sludge, soak it in gasoline, and if you are rich, use carb. cleaner, then wipe clean. Next, use q-tips to clean out the fitting hole or a piece of 14 guage copper wire, bent in a hook, to pull away the sludge. If any loose sludge falls in, fit your vacuum cleaner with a small polypropelene plastic tube (the hard plastic used for water plumbing), and suck out the loose stuff.

That's the tip of the iceberg. If the ALDA signal port looks like that, the interior surfaces of the intake manifold are like that from years of EGR function. It is speculated that clumps of goop slipping into the combustion chambers is what causes the 3.5l 603 to get it's nickname.

Sixto
95 S420
87 300SDL

Do a search, but pulling the manifold and cleaning it is the best way to go. Also block the egr.

The 2.5 might have one of those systems that cuts boost when you disable the EGR valve.

Sixto
95 S420
87 300SDL

How do I pull it out?

There is no screw to loosen or fasten.

By the way, the hose looks fragile. It has tiny suface crackes. I get a feeling that I may develop a puncture if I bend it several times.