Superglue can be used to fill/ seal small cracks and voids. I like the gel kind, as it doesn't run all over the place. I use a toothpick to push it deeper into the crevices; sanding after to clean it up.
Any sandpaper can be used, really. I prefer wet/dry just because it seems to last longer. (assuming you're doing this by hand) For simple refinishing I would start at 220 or 320 grit, depending on how deep any scratches are. Move up to 400 grit, than 600 grit. All these can be found at Lowes or Home Depot. I would recommend going higher to get a nice shine. You can find 800, 1000 and beyond at an automotive parts store, or online. 3M sells sets, as well as the micromesh brand.
If you're actually looking to reshape, as you suggested, you may want to start lower, to remove material faster; but this will take much more work to clean up after. The goal is to remove the scratches from the previous grit before moving on to the next; can be tedious.
I usually use some kind of oil/ wax blend to condition all my handles periodically; helps keep them lustrous/ keeps them from dulling.
Hope this helps!