The Basics:

Make sure your guitar or bass is kept clean. The best way to clean your instrument is to get a nice soft cloth that doesn't shed. Like a soft terry or white cotton sock. You can use the felt cloths but make sure it isn't treated. Remove the strings. (We will clean those separately.) Wipe the surfaces with the dry cloth to remove body oils like fingerprints and such. For those tough spots where you spilled your beverage (or drooled) use alittle bit of mild soap and water. Avoid using cleaners or polishes unless your guitar is already smudge free. Polishes just move the oils and smudges around the guitar. You want to clean those off first before you polish the finish. If you have an oil finish on your guitar, like the fretboard, neck or natural oil body, you may want to use a little bit of Murphy's Oil soap and water to get it cleaned up. Don't forget to clean around those frets! Drag a dry clean cloth over the entire guitar to make sure it is dry. Then polish if you like.

Strings:

It is always best to replace your strings in the ratio as to how much you play your instrument. In other words, if you play your guitar everyday  you may want to replace those strings once every two weeks. If that isn't an option you can clean them in between replacing them.

To clean your strings use 91% rubbing alcohol (from your local drug store) and a terry cloth or white cotton sock. Pour the liquid onto the cloth and run the string through the liquid on the cloth back and forth several times. You will see a nice black mark on the cloth when you are done. Repeat this until the black is gone or just light gray. Do this to all the strings. This will add some life back into them for a short while. This is not a fix all but is good when funds are short, especially for you bass players. Please do not "boil" your strings. This is time consuming and your strings will end up rusting in the core and breaking. Soap and water seems like it would work but you can never quite get the string to dry completely. I do not recommend anything to clean your strings that is water based.

Starter Series Basic Guitar String Set Up for Acoustic Electric Guitars DVD

Digital Guitar/Bass Tuner

Electronics:

If you dare, you can clean up under the hood of your electronics. Do not use a cloth of any kind in the cavity of the guitar that holds the wires and circuits. I recommend compressed air and a spray electronic cleaner. If you must clean out the dust and goo, use these sprays. Techspray Duster. Non-Flammable, Non-ozone Depleting, Moister-free gas. Always keep the spray can in an upright position. Even though the can says it is a "gas" it is in liquid form inside the can.