I was salvaging some pocket screws from a project gone wrong that had been sitting outside, and I noticed some of the screws were a little rusty. They are the regular silver kreg coarse threaded screws for 3/4" material, not the blue ones.
Are they ok to re-use or is their integrity compromised because of the rust on the threads?
Are you sure it's rust?
Seems like oxidation has formed on the screws being exposed to high MC damp environment.
Clean off the discoloration from the screws, using a rotary wire brush, Dremel or the like,
and coat the screws with spray lacquer.
Place the screws on 1/4" wire hardward cloth screen, spray away and allow to dry.
(Placing the screws on the wire hardware cloth screen will allow the screws to be slightly elevated and make only point contact at various places on the screw.
Some inexpensive pocket hole screws are coated with a flash of chrome.
Chrome developes surface rust, when exposed to moisture.