I found these copper scrubbers at Walmart. They were cheap and in the right shape. They scrunch down & pack into the tube nicely. In retrospect it would be better to center them on a metal tube of the right length so the entire assemble could be pulled off the base[attachment=56556]20200101_125931.jpg[/attachment] casting readily if needed.
I just disassembled my fuel tank cap and it has some similar stuff in it. I was gonna try to clean it but that looks like it will work just fine. Thanks