Adjusted the tension on the RD yesterday, and went for a quick 2 mile ride up the road and back to ensure no issues while shifting. That seemed to be the problem, indeed. When I got back, I just took a rag and wiped excess grease off the rear cogs and bottom portion of the RD with a plain old rag (old XL T-Shirt from my fat days), got it pretty clean - I'll probably use a can of White Lightning Degreaser before I put the bike away for the winter.

I use sisal twine to "floss" the cassette. It's cheap and the thickness and texture of the twine really grabs the gunk. Cut 4 or 5 foot-long pieces and get flossin'. As mentioned above, if the cogs are really dirty a light misting of WD40 really cuts through the grime. Shiny clean in no time!

http://bikeforums.net/attachment.php...hmentid=339197
+1 on Chain-L for a silent drive chain.