Take them apart, one at a time so you don't inadvertantly mix parts.
Note what jets you currently have in them, ie., pilots, needles, needle clip position and mains.
Use carb cleaner and wear safety glasses.
Pull the floats off and the needle of the fuel inlet needle and seat.
Use some toothpaste on a q-tip to polish the seat.
Use compressed air to blow every orifice out completely.
If you're talking about stock carbs, i recommend ordering new OE bowl gaskets and switch out the bowl screws to allen heads.