What is the best/fastest way to remove the rubber gasket/weather strip in the trunk rail?

Just grab and go. Unless it stuck

It's stuck. I was hopinmg someone new of a solvent to use

3M makes an adhesive remover as do several other companies. Pull off what you can, and then test a small area to be sure the adhesive remover doesn't also remove your paint. Then, you've got to employ some elbow grease as you use the adhesive remover. I've used a narrow plastic screwdriver as well as a narrowed popsicle stick. Naptha may also soften the adhesive. Lacquer thinner, acetone and tri-chlor will remove your paint.

Let us know how it goes.
Andrew Offutt

Andrew, thanks for the info. As for removing the paint, that's part of the reason. I'm removing the gasket for body work, primer and paint!