I had 3 of the 126's (89 560SEL ,cherry, 105K miles sorry I sold it). A good permanent solution is: Remove the offending plastic trim that is on top of the wood . Lay a coating of paste wax on the wood. Clean the rubbing surface of the plastic with brake parts cleaner on a rag. . The put a layer of clear silicone rubber on the plastic and allow to dry overnight. Then reinstall.

Nothing permanent for door jambs and door gaskets. Regular applications of spray silicone lube works for several weeks/months. The fact so many folks ***** about this is testimony to the ultra reliable nature of these cars -- nothing major seems to be a real big issue.