In this article I will present the main products to clean your instrument. We can count 4 main types of finish: french polish (generally found on classical guitars), nitrocellulose, polyurethane, and oil. It is important to identify your type of finish before starting to use these products.
Keep in mind that it is preferable to clean your instrument after every instense use (perspiration), to avoid having to use harsh products.
Unless it is made of maple, it is not laquered. Often, a thick black layer builds up on the on the parts most heavily used. You can begin with alcohol on a clean cloth, and change it once it is dirty. A few minutes are enough to remove the accumulated dirt. For more details on cleaning the fretboard, consult my article (“How to adjust your guitar”).
2) Oil finishes
The oils I use are: lemon oil, walnut oil, linseed oil. They can be found in any hardware store. Walnut oil seems to me more gentle and less toxic than lemon oil. All three products will hydrate the wood very well and must be done every trimester or semester, after a deep clean. Apply with a clean cloth, and use another one to clean off the excess (watch out, a single drop is enough!)
3) The body
For more delicate finishes (french polish and nitrocellulose), you should prioritize using a soft cloth lightly humidified with hot water. A bit of soap (liquid dishwashing detergent) can be added to the solution. In certain cases I use “Meguiar’s” products but I advise against using these as they are abrasive products, to be used with great precaution.
To clean a modern polyurethane finish, there are few restrictions. These are solid and thick finishes, with excellent impermeability. In this case I recommend buying a product such as Dunlop 65 or “Meguiar’s” number 34. For occasional use, again, a mix of hot water and soap is quite effective!
Naphta (camping fuel) is a gentle product on surfaces but highly toxic for you. It evaporates very rapidly and can be useful in certain cases. Whenever possible, I prefer replacing with alcohol, which is much less toxic.
Warning, both these products are highly flammable!
If you have a very grimy or old instrument, or if you don’t know the type of finish, contact your luthier so as to not damage it. If you have questions contact me by phone or email, I will gladly advise you as to the best solution.