The grunge movement made famous in the 1990s by music acts such as Nirvana and Pearl Jam isn't limited to the music or fashion inherent in that decade. There's another popular "grunge movement" that has an even deeper history -- the art of painting and treating wood so that it looks rougher and older than it actually is. This grungy wood complements home decor all throughout the world, and is within the reach of anyone who prefers its style.
Clean the wood. However you chose to grunge-up your wood, it's best to first prepare the wood surface. Remove all grease and dirt by washing it with a light detergent or surface cleaner. Purchase either at a paint store.
Sand the wood. Find a finer grit of sandpaper, such as 180 to 200 grit, to create a more worn instead of a scratched look. Focus on the raised areas of the wood that would have naturally been weathered more readily because of more exposure. If you're distressing painted wood furniture, for example, focus on corners and sides. For larger flat areas, pick random spots to sand. The goal is to reveal underlying wood or paint that complements the surface color.
Buy some crackle. You can get it at craft stores or home improvement stores. The basic idea is to apply the crackle between two layers of paint. This gives a rougher texture to the surface that resembles the rough spots that may occur after painting wood multiple times. Each crackle product may have its own specific procedure. Follow the manufacturer's instructions.
Chip the paint. Rub an old candle or other wax object on the area where you want the paint to chip. Then paint a new coat of paint on the wood. Let it dry sufficiently. Then scrape the surface lightly with a putty knife. The areas where wax was applied will chip easily and reveal older paint or the wood's texture underneath.
Give texture. After putting a fresh coat of paint on the wood -- which you should always do after you've given the wood a light sanding, so the paint sticks better -- mess up the paint a bit. Throw a powdery substance, such as flour, sawdust or sand, on the wet paint to thicken it and give it some texture. This imitates the uneven weathering and layering of paint that appears on wood over time.