I put mine behind my machine in a big glass canning jar.
But I did have the weirdest thing happen this morning when I was winding bobbins. I had the giant thread cone in the same jar as a small cone of invisible thread; I only threaded the cone onto the bobbin winder and somehow it picked up the invisible while it was going and wound them together! Like some kind of weird thread magic ... I had to take a razor blade to the thread to get it off the bobbin. :!: