For dome plugs, like most Minnies use, I do pretty much what Kevin said, with the exception that I drive a punch or a sharpened screwdriver blade through the center of the plug and then lever it to the side, which pops the plug out.
I put them back in by tapping the plug into place against the shoulder in the hole, then placing either the ball end or the other face of a ball peen hammer (depending on the size of the plug) and striking it with another large hammer. It usually only takes one or two whacks to seat the plug and you DON'T have to come all the way from Gergia when you hit it either.
I usually coat my plugs with some kind of sealer too.
If its a lip-type plug, like lots of cars use, I use a flat punch on one side and drive it inward. That usually causes the plug to twist in the bore exposes the lip on the opposite side that can be grasped with vise grips and lever the plug back through the hole. I use a socket or a piece of pipe that is close to the od of the new plug as a driver to put the new one back in.
Some other thoughts: If you have to pull the 'jugs' to put plugs in, you need to replace all of them, because if one has a hole probably the rest are rusted thin as well. They rust from the inside out.
Last thought: if you are using it and need it quick, I have seen expandable rubber plugs like you can get from the auto parts store in some of the late MMs.