I don,t have a Commuter ped but the Puch has the black lever also, operates the starting clutch. It is slightly loose from wear but Mine doesn't need fixing yet.
Looking at mine it is held in by a roll pin, If I were to fix it I would knock out the roll pin, then measure its diameter. I would then find a brass insert that was 1mm larger and drill the hole for the size of the pin. I would then get a drill that size and drill out the hole in the handle. Lube the insert with grease, put the insert in the handle, put the handle in place and drive in the roll pin.