How much is the throttle cleaning of a BMW?

How much does it cost to clean the BMW throttle once? The following is my personal opinion:

BMW's throttle is cleaned once, 400 yuan. Cleaning method of BMW's throttle;

1, buy a bottle of carbon cleaning agent from a reliable source, open the front cover, find the engine and air filter tube, and loosen the hairpin screw near the engine side of air filter tube. Now you see the electronic throttle connected to the engine;

2. Spray the cleaning agent on the electronic throttle, wipe it with deerskin cloth, repeat the operation, and clean the parts that are difficult to wipe with cotton swabs;

3. Turn the car key to the on position and continue to wipe it until the black substance inside is cleaned. After wiping, let it dry for a while. Finally, reinstall the air filter tube hairpin and tighten it. Ok, the cleaning work is finished.