Is it safe to use water to clean (rosewood, ebony, maple) fretboards?

Question

It's common to see in message boards, forums, and news groups that using water to clean a fretboard can cause problems, or is otherwise advised against. It's not normally explained why, or if it only applies to some types of woods, and normally given as advice in non-formal contexts.

Even when you are not using water to clean the fretboard, it can get wet from cleaning the strings, or other parts of the guitar.

There's a lot more info about oils, but not much about water. Long-term, excess humidity can negatively affect the guitar, but is cleaning the fretboard with a wet rag dangerous for the instrument? Why / why not?

Answer 1

It is generally safe to use a lightly dampened rag on your fingerboard.

Getting the fingerboard wet can cause problems, specifically in your fret slots where any swelling or softening of the wood may cause loose or popped frets. On a lacquered fingerboard if water gets into any chips or cracks in the lacquer it can cause lifting of the lacquer or staining.

It is a generally accepted practice among Guitar techs and luthiers to use Lemon or mineral oil when cleaning dirty, un-lacquered necks. The oil isn't necessary to the condition of the wood, but it does make removing oily dirt easier, and leaves a nice look afterwards. Oiling a fingerboard should not be done too often however, about once a year is usually enough.

Further cleaning of the fingerboard may be done with 0000 Steel Wool, often used with Lemon or mineral oil.

For lacquered fingerboards the same cleaner you use on the guitar body will work.

Frets.com has a good tutorial on guitar cleaning

Answer 2

A damp (not wet) rag should not cause any issues with most guitars - but, it's not going to do too much, in my opinion. Most of the dirt on a fingerboard is from oil off the users fingers, so you need a (gentle) solvent to clean that off. Personally, I use Lemon Oil for that (or, in a pinch, Olive Oil)