How do you reset the check engine light on a 2003 c230?

I have a 2000 C230 with 93,000 and the engine light came on. Before going to a dealership and getting consumed try the following because it worked for me. I purchased Chevron Techron Fuel System Cleaner and put it in the gas tank when it was almost empty. I drove the car for about one week and the check engine light went off. The reason was the Fuel System cleaner works well to keep the gas clean and as a mechanic told me, it often takes 15 - 20 cycles (drives) before the engine light corrects itself. It took about 5 days for the problem to stop but hope this experience helps.