Looks worse than it really is, but there's probably all kinds of corrosion and crud inside the little passages too. What to do? Zitrone Partei!!!
Step 1 - Wait til your wife isn't home
Step 2 - Fill a pot with a bottle or two of straight lemon juice from your local grocery store. Start it heating, but keep an eye on it because once it starts boiling it'll foam and overflow if you don't turn the heat down.
Step 3 - Fill another pot with a water/baking soda solution to neutralize the acid after you clean the carbs. Stir in baking soda til it won't dissolve any more in warm water.
Step 4 - Once the juice is boiling turn the heat down to a simmer and dunk your parts in there. Keep a close watch on it that it doesn't foam too much or you'll end up with a hell of a mess.
Step 5 - After 10 minutes or so per part, take the part out and run it under the faucet to wash off most of the juice. Dunk it in the baking soda solution, then rinse it again and blow it out with an air hose.
And now I've got spotlessly clean carbs inside:
At this point I could have cleaned up the outsides more, but then they would look wrong on the bike. All I wanted to do was get all the corrosion and old gas out of the little tiny ports everywhere, and lemon juice does just that. No scrubbing at all, just dissolves it away.
More to come soon...