Hi
pretty much had the same situation on Skruffy Kat. The old petrol had dissolved the little rubber bungs.
At the time I had access to a hooge sonic cleaner, so dropped the whole bank in the bath and over a period of days cleaned them out. I then rebuilt them with the kits available from NRP (KOC discount) had all the bits I needed.
But before I fitted them to the bike I set them up on the workbench and filled them with 50-1 2 stroke mix. Because it was a vivid pink colour. Good job realy as the "nipples" connecting the carb bodies leaked profusely
So I separated the bodies and replaced all the O rings. They went back together easy enough, just need to balance them up now. Be aware that the screws holding the bodies together a thread locked and a quality screw removing device should be used. Also thread lock them on re-assembly.
As for other people doing the job- I have heard someone quote about 25 squid per carb, but not sure who. You could try CC's
http://www.carbcleaning.com/index.asp" onclick="window.open(this.href);return false;
not used them so cannot say either way. but they have been used by some of the magazines