I got tired of buying the plasic bobbins that the craft store puts out, so I decided to make some out of cereal boxes... not sturdy enough. Pizza Boxes, though, are definitely nice and sturdy! I use the ones from our Aldi frozen pizzas, so they're clean.
I like to make sure I put the slit on the side without the holes, and that I wrap the thread following those lines. If you do it the other way, it has a tendency to bend, when you're wrapping the thread.
