You can buy cork and rubber plugs at your local hardware stores or online. However, as you can see in the picture finding the right size is difficult and has left this piggy in the air, dangerously off balance.
Step 1: Materials and Tools
* Cutting tool: hacksaw, razor blade, but I liked using a hole saw in a drill press
* Compass or other means to draw a circle if not using a hole
* Pencil, pen to draw circle on sponge
* Anything to measure the diameter of the plug hole. Ruler, calipers, tape measure
Step 2: Cutting Out the Plug
If using a drill press or drill with a hole saw be VERY CAREFUL. The saw can grip the sponge and yank your hand/arm into it and hurt you or worse. Keep your hands clear of the sponge. Using the hole saw on my drill press I simply turned it on and slowly advanced the saw. It cuts easily, just don't go too fast so it doesn't grab the sponge.
My hole saw and drill press wouldn't plunge all the way through. I freed the cut plug from the remaining part of the sponge using a box cutter. You can see that one end is jagged compared to the rest so I just cut that off with the hacksaw blade.
The sponge does "flex" while cutting and can make things a little askew but again - it's just a piggy bank plug.
Step 3: Plug That Pig!!!
I'm sure I'm not the only one to have done this. I just happened to think about it and then did it very quickly. It worked out so well and it was so quick to complete I thought I'd share. I hope you liked this instructable thanks for reading.