Improve the Tone and Appearance of Your Guitar: How to Clean Your Guitar

What's the easiest and cheapest way to improve your guitar's tone and appearance? Clean your guitar. Accumulated dirt, perspiration finger oils can mar the quality and resonance of your acoustic or electric guitar.
To Really Clean a Guitar, First Remove the Strings
Each time you change strings, it's a great opportunity to clean your guitar.

• You have clear access to the fretboard.
• You don't want to contaminate your strings with the oils, polishes, cleaners or cloths you're cleaning with.

If you have a guitar with a floating bridge, remove three strings and clean one half of the fretboard at a time. You only need to clean the guitar's fretboard once or twice a year. So if you change strings often, don't clean the fretboard at each string change. Start cleaning the guitar by wiping your fretboard with a soft, damp cloth. Take an old t-shirt or sock, wet it, and wring it out completely. Work the cloth down the fretboard, readjust the cloth so you're using a clean portion of cloth at all times. If your fretboard has accumulated grime, follow the rag cleaning with a very light brushing with some extra fine #000 or #0000 steel wool. However, before using steel wool, you must cover up your magnetic pickups. Else, tiny pieces of steel wool might stick to the pickups. For hard-to-reach spots use cotton swab, toothbrush, or credit card edge.
Don't want to be obsessive about cleaning your guitar's fretboard. The oils and moisture from your hands actually condition the wood. If your fretboard is dried out or has developed hairline cracks, rub a drop or two of mineral, almond or linseed oil into the fretboard to condition it. Make sure to wipe off excess oil with a soft, dry rag. All you need to clean a guitar's body and neck is a soft, dry cloth. If the dry cloth isn't enough, you can use a well-wrung out damp cloth. Clean the top, back, sides and the neck.
Really, Really Clean the Guitar: Polish the Finish
Several times a year, you may want polish up your guitar, but it's not necessary. Many guitar makers finish their guitars with several coats of a high-quality nitrocellulose lacquer. This finish ages nicely without polish. If you decide to polish your nitrocellulose-finished guitar, use a product designed for nitrocellulose finishes. Apply the polish onto a rag, not onto the surface of your guitar. Never use a furniture polish on your guitar, this could actually affect the resonance.