My '86 240DL sedan just turned 290K miles recently. I bought it from its original owner at 180K. He had its entire service history and is a beautifully running car. I keep it serviced regularly and change the oil every 2500 miles and use a Mann oil filter. The only thing I cannot find it ever having had done was the throttle body serviced/cleaned. I do all my own work on the car and is this something I can do or should do even if it appears to run OK? How do I go about doing it?

Thanks for your input.