We report the first implementation of aninsituglow discharge cleaning procedure for the removal of carbon contamination from x‐ray optical surfaces.Insitucleaning obviates the need for the time‐consuming and costly process of element removal, cleaning or repolishing, remounting, and realignment usually necessary to restore x‐ray optics to their original condition. The apparatus required is quite simple and can easily be fitted to most existing UHV (ultrahigh vacuum) mirror boxes or monochromators. Results with several monochromators at the Brookhaven National Labs National Synchrotron Light Source (NSLS) show that better than original performance can be obtained at the carbonKedge, since the elements are not exposed to atmosphere afterinsitucleaning and do not accumulate the adventitious carbon layer associated with more traditional methods. Possible improvements and extensions of the technique are also described.