Some of our instruments have necks that are finished with a glossy or matte polyester finish. These necks can be cleaned and maintained with a polish cloth similar to the body of the instrument.
However, many of our necks are not finished that way. They are finished with tru-oil and gunstock wax for a smooth natural feel.
For routine conditioning and cleaning of these necks we recommend Ernie Ball Wonder Wipes Fretboard Conditioner.
If the Wonder Wipes are not available try using a high grade of lemon oil. It will work both on maple, rosewood and ebony. If the neck is very dirty, you can use a small amount of Murphy's Oil Soap, diluted 3:1 with water, to clean it. Keep in mind that if the dirt has gotten into the wood, it cannot be removed except by sanding it down, which we do not recommend a lot of. It is better to keep it clean in the first place. Washing your hands first helps!
On an maple neck, some discoloration after many hours of playing is normal.An annual (or so) dose of tru oil and gunstockwax will help to keep the neck maintained; we use and recommend Birchwood-Casey Tru-oil, but any good quality gunstock oil will work.Here is a video showing the process.
Birchwood-Casey products are available at most sporting goods or gun stores, or now you can order them direct. Their web address is http://www.birchwoodcasey.com.
Be sure to follow all of the manufacturers recommended safety precautions when using any oils or waxes.