fretboard maintenance  

Cleaner? Are you saying you have gunk on your fretboard?
Is it rosewood or maple?
On rosewood I use Old English Lemon oil. You can get in your local supermarket or hardware store. Just pop some on a lint-free rag (like and old, well-washed cotton t-shirt, and wipe the neck down with it. Be careful- don't use a lot of pressure or accidentally dig in with your nails - you may damage the rosewood. Let it soak in for a few minutes, and then buff it with the clean side of same rag, gently!

On maple necks: they should be sealed with varnish or lacquer or even poly, so all you have to do is use a lightly damp towel to wipe them off. If you have wear-throughs (where aged bare wood is showing thru, and looks grey) be very careful not to soak the wood with water! Just a quick wipe with a dry rag is all you can do. If you use a dampened rag, the bare wood will swell and damage the fingerboard surface.

i just using eucalyptus oil to clean my guitar after using it to play.
its cheap and i recommend it because its good for the sound of the guitar.

It´s a lemon oil cleaner & conditioner and the brand name is D´Andrea, it´s good in my opinion.

I too use lem oil. I apply it when I change strings every other week or once a month depending on how heavily I am playing.

I also have issues with my hands sweating. The best thing I can recommend is to use the lem oil, wash your hands before playing the guitar and try to keep a soft dry polishing cloth handy for wiping your hands and the guitar neck down with when it's starting to feel like a slip n' slide.