SIL-GLYDE from NAPA stores is probably the best thus far for this application. It has all the desirable properties,
non-melting,non-freezing,non-gumming,weatherproof,effective from -20* to +600*F and harmless to rubber. The best method
for applying would be from the 4oz. tube brushed on and than on a regular basis every six to twelve months. This stuff is great on all rubber seals to doors, trunk and engine compartment. All rubber bushings, speedometer cables, brake pads, calipers etc. etc.!!! I can`t say enough for this product so see for yourself.