66 Dart owners, what did you do?

On the rear moldings that go up along the rear quarters there are 8 clips that hold the trim down. So tonight I put mine on but was unable to adjust to fit so I removed them and found that the clips are adjustable and the bolt part of them should slide back and forth to fit trim on correctly. Each clip has a rubber gasket and of course since mine are over 50 years old they were hard as a rock and pasted to the clip not allowing bolts to slide in the clip. Here are the pics of what Im trying to explain the first pic is the actual clip with the hard rubber washer pulled part way up
DSCN0961.JPG
here you can see that the bolt has a slide built into it with bolt slide all the way back and the one beside it rusted in place DSCN0962.JPG
In this pic you an see the bolt moved to the front position. This allows you to move the trim to fit the quarter. DSCN0963.JPG
The washer is to keep the water from entering the quarter.
My question is what have others done. Does anyone sell a rubber washer that would work. I plan on visiting my local Ace tomorrow maybe NAPA, or another option would be to make some washers from an inner tube or something like that.
What have others done to refurbish they clips?

Rod