Q: By accident, I left a pressure-treated 2×4 on my spotless tablesaw for a couple of days. Big mistake! What can I do to remove the rust it left behind?
A: Here is a fast and simple technique for removing light rust. Pull out your random-orbit sander and cut a square about the size of your disc from a nonwoven abrasive pad. A green or dark-red 1/4-in.-thick Scotch-Brite pad is the right coarseness. The dark-red pads will last longer than the green ones. If your sander uses hook-and-loop discs, remove the sandpaper and press right down on the pad. If your sander has a smooth bottom for pressure-sensitive paper, put on a piece of coarse (60 to 80 grit) sandpaper first.
Before you begin sanding, unplug your saw and apply a lubricant to the rusty area with a paper towel. Mineral spirits or WD-40 work well,but put on no more than a very light coat.
Now, put on some eye protection. Turn on the sander and exert just enough pressure to keep the pad in place. The rust should be gone in a matter of seconds.
If this doesn’t do the trick, you’ve got two more options. First, try a light-duty rust remover as an alternative lubricant. If that doesn’t work, switch to a more abrasive pad or a sandpaper disc (220 grit or higher). Again, apply a thin coat of lubricant. Take it easy with sandpaper, because you will be removing a small amount of metal along with the rust.
When the rust is gone, apply a coat of furniture paste wax to your saw right away to prevent it from rusting.