Ooohh, great idea! Trying to think of how I could do that, and what I could use for the narrow metal containers (and to keep them in place standing up and not falling over). I'm sure I could think of something. I would have to come up with some way to anchor them well. Some subs think they're smart and they figure things out, and then they would just find a way to tip them over so they're no longer in contact with the weights. Need to make sure I account for that somehow. ;-)