I generally just use a stiff plastic-bristle brush to sweep away the insects. As mentioned above, the use of high-pressure water like at the commercial 'wand washes' or even the use of high-pressure streams of air from a compressor can bend the fins and make the problem worse. Just be gentile until you figure out what kind of stress the fins can take.

 

I read this thread this morning, and I decided to take the plunge on my '06 MCS, with about 16k miles on it.
I used Simple Green to clean the outside fins and casing, then used a gallon of acetone and swished portions in there a bunch of times. Simple Green only on the rubber boots on the ends.
WOW. Was it dirty
All sorts of oil came out, making the acetone cloudy and yellow. After a gallon, there is still some dried residue on the smaller intake side that I'll get with Brake Cleaner after it dries out.

So, I gotta ask... when do people decide to get an OCC? Is it based on the volume of oil? or fear? or OCD?

Am glad I did it though... thanks for all the good advice here.