I use spare Cat Boxes for working on my guns.
Mostly pistol work.
In fact.
I am tearing down a pistol this week and will soak all the parts in Vinegar mixed with Hydrogen Peroxide to strip off the existing finishes.
I am having a friend Parkerize the pistol since it is an old military revolver.
Back when I did my own Parkerizing , I use to use the Cat Boxes to do the finishing.
Plenty of room to work in , plus very stable and not easy to tip over.
Plus,
Like you said.
Very easy to stack and store for other upcoming projects.