Trying to freshen up a pair of NOS Trico wiper arms and blades which I have had for 15 years. Does anyone know what can safely be polished without cutting into any actual Chrome if any has been applied? It appears the slender part of the arm is Stainless (non-magnetic) while the cover over the larger spring portion could be flash Chromed? The blade material holding the rubber is magnetic (low-grade stainless?). Thanks in advance. Jack J.