Today, I conclude the two-part series on cleaning your guitar. Last week we covered the fretboard, bridge, and tuning keys. Now, let’s take a look at how to clean a guitar finish.
Whenever you play, or handle, a guitar, sweat and oils from your skin come in contact with the finish. Over time, these can build up and actually damage the finish. So, your beautiful instrument starts to look dull and hazy. The problem is that your sweat can actually cause the finish to break down. It contains salt, acid, and some minerals that are corrosive. If left on, the finish can be permanently damaged.
Can you clean it? Absolutely! If you do it right, you can preserve the finish of your guitar, but if you don’t, you can also do more damage than good. So, read on for some tips to safely clean your guitar’s finish. But first, here’s a bit of information on what goes into a finish in the first place.
Types of Finish
Many different types of finishes have been used on guitars over the years. Older, vintage instruments typically have a nitrocellulose lacquer (often just called nitro) finish which are hard and thin. The advantage of nitro is it allows the wood to resonate and can actually contribute to the sound. Nitro is made by nitrating cellulose, typically done by exposing cellulose to nitric acid, then combining the nitrocellulose with other resins dissolved in a lacquer thinner solvent. The resins provide both flexibility and durability. The lacquer thinner contains a variety of solvents, including acetone, naphtha, toluene, xylene, and a variety of ketones.
The major problem with nitro is the solvent which evaporates after being applied. Many of the compounds in the solvent are considered to be health risks, so care must be taken when used. A vapor mask and strong ventilation are required to safely work with nitro. Of secondary note, nitro is also prone to crack, particularly when exposed to sudden changes in temperature or humidity.
A number of companies have taken to using alternative finishes to avoid the health risks and environmental pollution that result from using nitro, but also to make the finish less susceptible to environmental changes. Various formulations now include acrylic, epoxy, polyester, or urethane. These tend to be more stable than nitro. Water-based finishes that use UV light to cure are growing in popularity since they use less chemicals, making them healthier to apply and easier on the environment.
All finishes are either gloss or satin. Gloss is, as you’d expect, shiny and glass-like. Satin has a soft look that can actually give the impression of being unfinished. The only real difference between the two is a satin finish has an additive that reduces the glossiness of the finish. Other than that, theoretically, they are the same.
When the time comes to clean the finish, there are several things you can try. I’ll start by listing the easiest approach, and move on to the harder ones.
Fingerprints and other smudges from contact with your skin are generally the easiest to get off. Wipe them down with a paper towel or a soft cotton cloth. I prefer an old t-shirt. If something happens to it, it’s no great loss. Plus, you can wash it and reuse it. (Interestingly, a recent article in Acoustic Guitar also recommended using an old t-shirt to clean with.)
If the dirt is a bit tougher, mix a drop of dish soap with some lukewarm water (not hot – the temperature could damage the finish). Sparingly apply it with the old t-shirt and rub the dirt off. For those hard-to-clean areas right up against the fretboard and bridge, use a Q-tip swab to get in close. Do NOT leave water standing on the wood – you’re inviting water damage to the wood itself. Make sure when you’re done that everything is dry.
If the dirt is stubborn and won’t come off with the diluted dish soap, then I suggest you use Planet Waves Hydrate (available at Amazon here). I like this product because it is non-toxic, non-flammable, and quite good at removing dirt. It’s also gentle on both the finish and any unfinished wood, like your fretboard or bridge.
Lastly, I like to use a microfiber cleaning cloth to give a good final shine to my finish. There are a number of companies that make these, like Gibson, Planet Waves, Fender, Dunlop, Music Nomad, Ernie Ball, and Cordoba.
To Polish or Not To Polish?
Many people believe that you need to polish the finish when you’re done cleaning. I’m not sure I agree with this. Many, if not most, of the products advertised as a polish for your guitar can actually do more harm than good. Avoid furniture polish or household cleaners, like Pledge or 409. There are several reasons for this. First, many contain chemicals, like petroleum products, that over time will actually cause the finish to deteriorate. If you must use a polish, get one that doesn’t have petroleum products or solvents. Or silicone or bleach or lacquer thinner… And the least amount of residue it leaves the better. And use it sparingly!
Second, you need to be careful if there is any cracking or checking of the finish, particularly with nitro. The polish will build up in the cracks, causing one of several problems. The build-up will draw attention to the cracks, and while that’s not damaging, it can make your guitar look bad. And who wants that? Plus, it can discolor the wood underneath, making it look even worse. On top of that, the build-up can actually cause bits of the finish to flake off, leaving the wood underneath even more exposed.
Frankly, there is not a product I will recommend here for the job.
A Caution for Vintage Guitars
If you have a vintage instrument… lucky you! Just know that nitro, when it ages, will change color somewhat, giving the finish a nice patina. If you try to take the finish color back to what you believe it looked like when new, well… don’t! In addition to running the risk of damaging a vintage guitar trying to restore it, you can also reduce it’s value.
So, that concludes my two part series on cleaning your guitar. Now that the entire instrument is good and clean, play it! Make music! The world is a better place with music, so do your part.