I took off the spare and back bumper, and then wire brushed and put rust restorer on the back frame and then a top coat, but when I went to hang the spare, I heard something sloshing around in the spare when I rolled it. Took it in for someone to take it apart and look at it, but they immediately knew it was 'balance beads'. I never even knew about them.
balance bead inside the wheel - Google Search
balance bead inside the wheel - Google Search