What a (rusty) screw up!

Well the photos really tell the whole story really :upset:. I'm gutted, I haven't even had a chance to use these yet as they've been sitting in storage waiting for the other parts of my machine to be cut.

Attachment 24147
Attachment 24148

The room they were stored in wasn't heated and I'm guessing there was some condensation. The one long screw (x-axis) has been hit badly and the z-axis isn't great. The other two have got off much more lightly though with only a few small spots of rust.

The big question then is do you think they are salvageable? If yes what is the best way to go about cleaning them up? I was thinking wire brush followed by a dowel wrapped in wet and dry with WD-40 as a lubricant.

You won't really know how bad the damage is until you clean them up.
I'd try a bit WD then a rag to start with, failing that, your best chance is likely to be to remove the nut, and use some electrolysis, as it'll dissolve the rust without resorting to abrasives.

All you need is a suitable container (gutter section works well for long narrow things), and a suitable power supply. It's not something I've personally done, but I've seen some remarkable results on a couple build threads in the past.