Keep Your Guitar Clean
After playing, wipe your instrument clean (using a damp, soft cloth) of any body oils, sweat, or other nasty stuff it may have come in contact with. Pay special attention to the area where your arm rests at the edge of the top and the back of the neck because these are high contact areas. Some finishes are more impervious than others, but regular cleaning is a good habit to get into. (Trust me, your repair luthier will thank you. Sometimes guitars come into the shop with so much funk on them, I have to wear latex gloves and make sure my vaccinations are current just to work on them.)
Cleaning the Body
For cleaning most finishes, I use blue shop towels, which are softer than paper towels, and Novus No. 1 plastic cleaner. Some commercial guitar cleaners work great as well, however it is important to make sure you’re using a cleaner, and not a polish, which might leave a smeary residue behind. If your finish is French polish, heavily cracked, or flaking off, don’t put anything on it until you get a professional opinion. When a finish is clean, it should shine on its own without needing polish, which can leave a smeary residue. For stubborn build-up, Formula 409 will help cut through the grime and is safe for most finishes. If your finish is still hazy after cleaning, some light rubbing compound can be used to get the shine back. Keep in mind, though, anytime you buff or polish your guitar with an abrasive compound you are removing small amounts of finish, so use sparingly.
Your fingerboard sees a lot of action, so keeping it clean and well maintained is important for optimal playability. Keeping the fingernails on your fretting hand trimmed will help you play easier and prevent divots from forming in the wood between the strings. Oils from your fingers can dry out the wood, and dead skin can accumulate against the frets, making little oval-shaped patterns. Like your instrument’s finish, the fingerboard is easier to clean if you do it regularly. When the strings are off is a great time for a deep clean and fingerboard conditioning.
For built-up fingerboard grime, I like to use Formula 409 and an old toothbrush with the bristles cut down to make them stiffer. Spray the cleaner on evenly, making sure not to get any in the soundhole where it could stain the label. Then attack the buildup in a circular motion with your toothbrush. This can be messy, so keep some rags handy to wipe away the dirty liquid (see photo). When you have a nice clean fingerboard, let it dry and clean off the toothbrush. If your frets are a bit tarnished or oxidized, some 0000 steel wool will make them shine again. I like to run the steel wool along the grain of the fingerboard over the frets, not side to side along the length of the frets. Be careful using steel wool around the guitar’s top, because it can easily put light scratches in the finish. If your guitar is equipped with a magnetic soundhole pickup, a piece of masking tape will keep steel wool from collecting on the pole pieces. When your frets are nice and shiny, blow off the steel wool bits and you’re ready for the last step. After all that cleaning, your fingerboard may be a bit dry. Lemon oil or mineral oil will do the trick. Rub it in with a paper towel until the board looks good but is not saturated.
Excerpted from Acoustic Guitar July 2013