Most of the time, all you need to do is to wipe down your guitar periodically with a soft clean towel. We use soft clean terry cloth or cotton t-shirt material here in the shop. Terry cloth has much more surface area to pull the dirt off the instrument. We have found that it works better than micro-fiber cloths.
If you have some gunk build up, you may need to use a solvent or cleaner to get the stubborn stuff. We suggest that you do not use household or harsh solvents on your instruments or any instrument.
In the shop, we use Naphtha solvent to clean most of our finishes. Naphtha is sold in most hardware, paint, and home improvement stores. It is also the main ingredients in Zippo style lighter fluid.
Remember to always test your finish with the solvent in a inconspicuous place on your instrument.
Just apply a small amount to a cloth and wipe off the gunk. Once it dries, there might be a film which can just be wiped off with a clean cloth.