I recently purchased a Parker Duofold Jr from a seller at the flea market. The pen was in good condition. However I did notice that the hard rubber cap had a few thin cracks all over its lip. Is there a way to repair them by chemically welding them or are then any other methods that will give a solution to my problem? Note that the previous owner thought it would be a good idea to super glue the crack which of course didn't work due to the oxidization of the hard rubber. I placed some photos below so you can see the cracks.