Florey, I've done this several times. Use a sharp 1/2 inch wide chisel centered on the plug and lined up with the grain of the plug and tap it straight in with a mallet. The plug will split in half and the pieces will fallout with just a little help. They were just glued in and come out pretty easy.
Salt Flat
Awesome Salt Flat - you are a lifesaver. Thank you very much. Cheers from Sunny Australia