If your home has unsightly plank wood walls, slowly turning you in to Jack Nicholson from The Shining, no need to get out the axe and tear the wall apart. With some patience, they can be refinished without hiring a professional. Use an orbital sander to remove the existing finish, wipe away dust with a damp cloth, then use a stain pad on an extender pole to add the new finish. To go gray, you'll most likely have to have a semi-transparent stain custom mixed; you'll also want to lightly sand between coats to ensure that perfect finish. If you go too light, the gray can come out a little blue or green, depending on your wood tone. Stick with medium gray; many manufacturers label this "slate."