I have had my classic for about two years, and don't do anything to it other than wiping dust off the guitar and replacing the strings when needed(about every month or so).
I've had a sponge type of "thing", they called it fret cleaner. I normally wiped it over the strings gently and wiped the excess off with a cloth that came with. That did not do much for the fretboard itself, but the strings appeared to last longer against corrosion. The fretboard only became like slippery, and my slides tended to go further what I expected - so I dropped that all-together.
I want to know what would the best chemicals would be to clean an classic guitar. The fretboard, being made of a plastic substance, doesn't absorb oils, and it only makes it more "slippery" as I said above. Currently I use normal wood oil for the body, and don't do anything to the fretboard apart from wiping it with a damp cloth every week.
Is there anything else I need to do in order to perform better maintenance on my classical?