I have this Telecaster pickguard that doesn't fit my Telecaster slightly. What tool would be most effective for cutting through it?
Best tool would be a router with the correct bit and a template. Since you don't have that, I'd recommend using a Dremel Tool... again, with the correct bit. If you don't have that, you'll have to use a file, or sandpaper.
Sandpaper it is. Thanks mate.
sandpaper will take forever, use a file