I bought an unfilled grappling dummy for my kids to practice on. Any suggestions on a good filler to stuff it with? Old clothes is the plan right now.

Old clothes work great. It takes a fair amount to stuff though. We used dummies during some of the covid restrictions here (weren't allowed to practice with partners for awhile) try here https://allrags.com/produ[...]6520728272 or google 'rags bulk' for something in your area.