Neil,

I'm currently gearing up for another round of long travel, and I haven't had a chance to dig into it yet, but my plan is to try the magnaflux method first if it's at all viable without specialized equipment. Mostly because it's completely non-destructive.

At first blush it looks like this'll be a pretty easy method -- I've got an absurdly powerful neodymium magnet (and some less absurd ones too) and this whole hobby of honing razors makes it very easy to get a suspension of ferrous particles.

But I should probably get some HCL for restoring etches anyhow, and then if the magnaflux trick doesn't work, I'll move on to the bigger guns.

I'll update here as I do the tests. If the magnet trick is as easy as that article makes it sound, that could be a truly excellent way of pulling lost marks off razors.