Homebrew PCBs

I have a project idea that would require hundreds (possibly thousands)
of very small PCBs, each one being a circle approx. 1/2 inch in
diameter.  Does anyone know if it would be possible to punch them out
of thin FR4 with a punch press?  That is, use the material that is
normally discarded when punching out a hole.

Aside from that, what (if any) are the issues with using thin (0.010"
- 0.030") PCB material in general?

-p.