I went to the hardware store last night and got a lot more sandpaper, a wooden dowel to help with sanding out the seat tube, and some work gloves. Today I tackled the down tube, which still had a couple of stickers on it.
I’d previously removed the bike parking sticker with a putty knife, but the sticker from the store where I bought Ol’ Paint 10 years ago was more tenacious. It’s held up better over the years than any of the paint has. And to make any progress, I had to scrape with the putty knife until I was scratching the steel. Then sand like hell to remove any last trace.
The maker had also put some kind of stencil in the paint just below the top tube. In this case there was nothing to scrape at, so I just kept sanding until I removed all traces. In both cases I’m less concerned about removing the advertising (although less is more, and definitely so on this project) than the fact the new paint will probably not adhere properly to the old stickers.
One entire sheet of #120 later, I’ve removed all traces of the stickers, and got rid of the rust on the seat tube. The area around the seatpost clamp needs a lot more work, and it probably wouldn’t hurt to spend more time smoothing out the gouges from the front derailleur clamp. But I’m done for today.