I would put that Tales of Suspense off and try to find a coverless copy of it. It makes me happy that the Superman annual turned out well. I've found that even with light usage magic erasers will often take off some of the cover gloss, this is why I now only use them to clean my stove top and the front of my fridge.

Get a NOCO Genius Battery Charger, I have one that brought a totally dead battery back to life and you can also use it as a maintainer.

Thanks for explaining the sewing  interfacing issue...I have slowly been collecting supplies to give this a shot.  Also cool to know a bit about you. I am also a car guy who relaxes with my new found hobby of cleaning comics .

Enjoyed your process!