Bin it? Not hardly - that's just surface rust. However, if you don't get it all off, it's just going to come back from under your new paint. You need to hit it again with some coarse grit and continue until it's completely gone.

Look at it this way: there's not a whole lot of pitting going on, so that's a good thing. Check out the couple of photos below. Pitting all over this Guerciotti frame, but it's not a goner by a long shot - I've just got a crapload of Bondo work ahead of me





Good luck!

DD