If the prop is out of track then you have to sand the hub. If the hole is drilled at an angle, then you'll probably never get it right and should discard it.

If what you mean is the prop is out of balance, then you can file the sharp edge off 2 single edge razor blade and glue them to a couple sticks. Glue the sticks into a base. Then put your finger balancer on the razor blades.