I just cleaned mine the other week. It was actually super easy and fixed my sticking accelerator peddle.
1) Disconnect intake hose between air resonator and throttle body. This can be done by loosening the two clams with a flat head screwdriver. It will take some wiggling but it will pop off of the resenator and throttle body.
2) Disconnect sensor cable from throttle body
3) Disconnect the accelerator cable & cruse cable from throttle body
4) Unscrew plastic cover near throttle body
5) Unscrew the 4 bolts that connect the throttle body to the engine.
It should pull right off. On my focus it was made of plastic, so be careful what type of clearer you use. I used this: http://www.amazon.com/CRC-05078-Thro...dp/B000M8PYO2/
My focus is an 07, but I'm sure the 10 is similar.