Staining wood floor vents is both a pain and time-consuming, but here's a trick for dark-stained vents that makes it easy and fast. Take out the grill part of the vent, spray-paint it black and urethane it. Spray-paint the inside of the ductwork and the grill frame, too. When you sand the floor, the spray paint and finish will be sanded off the top of the vent so it can take the stain color (espresso stain was used here), and the inside of the grill will just look dark.
Thanks to Roy Reichow at Cedar, Minn-based National Wood Floor Consultants for his tip. Do you have a Trick of the Trade to share? Email it to WFB.