I recently took apart my Parker 51 vacumatic to clean it and replace the diaphragm (still looking for the right tool the remove the pump). When I eventually get it all back together, I'd like to avoid using shellac. While I don't anticipate opening the pen for a very long time, I'd still rather avoid having to melt the shellac all over again. Is there and alternative that I could apply to the pen that wouldn't harden over time? I'm thinking silicon grease might be the answer, but I'm not sure.