The tennis ball safe is a cool project to make. It is a pretty inexpensive project to make that only requires a few tools to make. This can hold a good amount of stuff. The size of the opening you make in the tennis ball is up to you. I went with about a 1 and a half in slit in mine. Make sure not to put where the dogs will grab it. There are a few different spots you can make opening in the tennis ball.
Step 1: Tools and Supplies
yellow fuss off a different tennis ball
stuff to put in side
Step 2: Making
Making the tennis ball hiding spot container safe is pretty easy to make. The first thing is start with your tennis ball and decide where to make the slit for where stuff will go inside. The length of this is up to you. I would say not to big but not to small. Using a razor blade is the easiest way to make the cut in the tennis ball. Hold the tennis ball in one hand and take the razor blade cutting a straight slit in the back side of the tennis ball. Make the cut clean so that when after the cut the ball goes back together making it look like there's not even a slit at all. Then if you have another tennis ball pull off some off the yellow fuse and roll it in between your fingers in a flat line. This can be placed where the slit is so that when the tennis ball is closed this will help conceal where the slit it.