Door Hinge Protection

While picking up my trim pieces the other day, the guy helping me mentioned a way to protect the door hinge. He showed me an old trailer with the original aluminum hinges. Basically it's a piece of rubber roofing mat that is glued to the outside of the hinge. It appears to serve two purposes. If keeps most of the dirt and dust out of the hinge. It also keeps the black streaks you get from worn aluminum from getting on the trailer. I was wondering if any one out there has ever tried this and how it worked for them? Thanks.
