Humidity and a sticky fretboard
As bodily fluids are not exactly the same from person to person you'll sometimes find that a specific remedy will work well for one person but not another person. For me, the following remedy works great. Whenever the fretboard gets a bit yucky I simply immerse a cloth into very hot water, then squeeze the cloth till it's only damp, then wipe the fretboard whilst the cloth is still very warm. Just wipe it over the top of the strings, back and forth a few times, and then wipe it again straight away with a clean, dry cloth.
There's lots of products that contain all sorts of chemicals, but I've found the warm, damp cloth method works really well for me. Hope that helps.
I've noticed in the recent humid days we have had here where I live that my fingers don't seem to want to glide across the fretboard as easily. The fingerboard appears to be a little tacky or sticky therefore my fingers kind of drag on it. Any tips on solving this problem?