The simplest type of guitar maintenance is cleaning. You should clean your guitar regularly or, at the least, every time it gets dirty. Keeping your guitar clean involves removing dirt and grime from all its various parts as well as keeping the finish smooth and shiny.
Cleaning away grime
Dust and dirt are part of your environment. Guitars definitely attract their fair share. Simple dust can be removed with a dry cloth or a feather duster, but when dust mixes with the natural oils of your skin, that dust becomes grime. Grime can stick to all surfaces, but it’s especially noticeable on your strings.
The strings: The natural oils from your fingertips coat the strings every time you play. Over time, these oils will corrode the string material and create a grimy buildup. Grime on the strings makes the strings wear out faster than normal. The grime impedes the way the strings sound and can actually seep into the pores of the fingerboard.
The best way to combat the grimy-buildup menace is to wipe down the strings after every playing session. Chamois (pronounced “shammy”) is a great material to use to wipe the strings because it doubles as a polishing cloth; a (clean) cotton diaper, however, works well, too.
Give the strings a general wipe down and then pinch each string between your thumb and index finger, with the cloth in between, and run your hand up and down the string length. This dries the string all the way around its circumference and shucks off any grunge.
The wood: A guitar is mostly wood, and wood likes a good rubdown. (Hey, who doesn’t?) Once you've blown off the majority of the dust, gently rub the guitar until it’s dust-free. To dust between the strings in hard-to-reach places, use a small camel’s hair paintbrush. Keep the brush in your case.
The hardware: Although grimy buildup doesn’t really hurt hardware (tuners, bridges, and so on), it sure looks bad — and you don’t want to appear on MTV with hardware that’s duller than your drummer. (Rim shot.)
Rubbing with a dustcloth is all you really need to do for your guitar’s hardware, but you can also use a mild jewelry or chrome polish if you want — as long as it’s not abrasive. Polish not only removes really greasy residue (which a simple wipe won’t do), but also brings the hardware to a luster.
Many inexpensive hardware components are dipped, meaning that they have a thin coating of shiny metal over an otherwise ugly and mottled-looking surface. So you don’t want to rub through the coating (which could happen with repeated polishing). And you certainly don’t want to get any liquid polish in the moving parts of a tuning machine.
Don’t ever touch the pickups of an electric guitar with anything other than a dry cloth or your dusting brush. Pickups are magnetic and abhor liquid as much as the Wicked Witch of the West did. You don’t want to risk upsetting a pickup’s sensitive magnetic fields with liquid, my pretty.
Caring for the finish
Acoustic guitars have a lacquer finish or other synthetic coating to protect the wood’s surface and to make it shine. Keep the finish dust-free so that it stays shiny and transparent for years. Don’t subject your guitar to direct sunlight for long periods of time, and avoid drastic humidity and temperature changes. Following these simple guidelines helps keep the finish from checking (cracking) as it swells and shrinks along with the wood.
If your finish ever cracks because of a ding (a small inadvertent gouge), take it to a repairperson quickly to prevent the crack from spreading like a spider pattern on a windshield.