I decided to clean up the drawer pulls a little. A very gentle rub with fine sandpaper not only took away what looked like a bit of crud stuck to them but also revealed a bright brass underneath. I hadn't expected to get back to shiny brass so fast (I tried rubbing with a cloth, which made no difference at all, so tried the sandpaper), so now I'll need to clean them up more fully and run the ultrafine polishing paper over them. If I don't like the way shiny brass looks I'll need to find replacements that will work with the existing holes in the drawers. I may need to stick with the bolts that came with them, because they use a non-standard thread that is proving difficult to match. I could potentially set up the geared thread cutting rig on my lathe but that would also involve cutting replacement heads for newly made bolts, which I'm not sure I really want to be dealing with. If I have to I will but it seems like an apocalyptic hassle.