Most guys end up using a small screwdriver to pry them out, which works but can easily scratch the bolts’ finish, leaving it susceptible to rust. The easiest way to remove them is to whack them square in the middle with a center punch. That’ll pop a small hole through the middle of the button and you can pop it right out. Of course, that assumes you feel like I do and don’t plan to ever use the plug again. If you want to remove the cap without damage, try this: Obtain a short length of monofilament fishing line (10-pound-test or stronger) or mason’s twine. Work the line under the cap, just like you’d use a hunk of dental floss. The cap should pull straight up without damage.