I USE fountain pens and COLLECT vintage hair toys (combs and such).
I use
RENAISSANCE WAX/POLISH on everything. It's a micro-crystalline wax that can be removed with a little white spirit. It's the ONLY thing that will restore lustre to Vulcanite (hard rubber) that I've ever found. It won't harm Bakelite or cellulose either. It protects and brings back lustre. It also fills small scratches. Museums use it by the bucket)
I have a friend that works at the Johnson Presidential Library, her job is waxing stuff with this wax. The amazing thing is that it is crystal clear so it can even be used on transparent parts.
When I get a new pen, I wax it thoroughly about 3 times with very thin coats. It protects the pen also.
I've purchased a beautiful Vulcanite pen that had become dulled with age. I cleaned it well with grain alcohol, then I polished it about 6 times and it looked gorgeous--so gorgeous that my son fell for it.