Cleaning throttle bodies?

[GG33]

WHat to use? and how? can it be done in situ or do they need to be removed? How often should it be done and what benefits can be expected?

So many questions - thanks

GG

[Funky Jo]

Before I had an engine rebuild I cleaned the throttle bodies about once per month (about every +/- 2000 miles).
Using a simple cotton cloth with maybe some aceton or simply petrol worked fine. The crucial thing is to open the butterflies (without de-adjusting them!) to really get to cleaning the insides. For this purpose I found pushing down the center screw (wearing gloves) of the mechanism down worked best. Alternatively you could have somebody pushing the throtle pedal down, or fix it with something stable and heavy enough. (It is not recommended to put a wood inside 1 or 2 of the bodies to keep them open.)
As a result I always felt the engine was running more smooth in general and especially more stable at idling.