Sometimes thrift-store finds clean up nicely!
I recently acquired a grungy Presto 21-B canner; it needed a bit of work. Of course, the gasket and over-pressure plug were old and dry and stiff. The gauge wasn’t sitting on zero and it needed a good old-fashioned cleaning.
When I removed the gauge, it stripped some of the threads out if it’s hole. I had to pick up an appropriately sized tap and die set (1/8 NPT) to clean up the threads so I could put in a new gauge. This resulted in the gauge turning ‘round more and facing toward the “back” of the canner. I used a Sharpie pen to draw alignment marks on the back side so I could still see the gauge.
Hopefully you can see there is less grunge on top of the lid than there used to be.
I used a bit of Bar Keeper’s Friend and a scrubbing pad on the rust stains on the inside bottom of the canner. A nylon brush and a bit of Dawn dishwashing liquid around the edges of the lid and the top of the canner, took care of most of the grunge.
See my 21-B canner page for the parts list for this canner and other similar models. I’ve also posted a scan of the 21-B manual.