Easy-pull holesaw plugs
Removing the plug from a holesaw can be a real chore. Here's how to cut a plug that pulls out with ease. First, drill a through pilot hole using a twist bit that matches the diameter of the holesaw's drill bit. Then, insert the holesaw's bit into that hole and cut just more than halfway through the workpiece. Withdraw the holesaw, flip over the workpiece, and saw the hole from the other side, using the pilot hole to guide the second cut. When you complete the cut and withdraw the holesaw, the plug will be halfway out of the saw, making it easy to pull out.
—Vell Holcombe, Milton, Pa.