If you don’t like the idea of running the tension rods through a tap, a gentler method is to use a 1/4” drive socket extension to drive a tension rod partially coated in a cleaner (I use Flitz Polish) through a double layer of terrycloth towel clamped firmly in a vise with rubber faces. Use a cordless drill.
I open the vise a bit, drape the folded towel down between the two vise faces, drip the cleaner along the threads on one side, then clamp the rod in the vise. The terrycloth has a rough enough nap that it gets in between the threads. Run it down and up twice, then unclamp and move to a clean section of the towel, and repeat without adding the cleaner (polish).
Josh
It takes time, but I am usually happy with the results.
