Heh. If you find a solution, please tell us! I've been making pickguards for many years, and I don't know a good solution to the problem of the sticking particles. I'll offer some help. A dust collector with higher air volume flow does a better job than a shop vac. The higher air velocity of the shop vac makes the static electricity worse. Many of the particles will settle in a few hours. Clean up the bulk of it right after you are done, then vacuum up more the next day. And the next.
I have a separate bandsaw that I use for only aluminum, brass and plastics. I never cut pickguard stock on my woodworking bandsaws. Too much mess to clean them up afterward.
Likewise, I have two small inexpensive routers set up just for cutting pickguards. They stay dirty with the plastic particles. No pickguards with any of my regular routers. I'm working on building up one of my tabletop pin routers just for pickguards. It's mounted on its own small cabinet on casters. I'll be able to roll it out into an open area, make a few pickguards, and then roll it back into a corner without bothering to thoroughly clean it.
If I made up a lot of pickguards, I would just rig up a closed booth with all the dedicated machines inside. And maybe use rubber gloves through a window, like a germ lab!
It is a horrible mess. I wish I knew the answers.