Wet sanding works well but is very time consuming. Working about a 6”x6” area at a time, 400 grit until you see wrap, then 600 until the paint is mostly gone. 1000 and up to 2000, then finish off with a headlight restoration kit. Fine polish with Novus. I did a whole kit a few years ago and had over 50 hours into it.
But hey, they were early 50’s Gretsch!