I just got a new guitar with a maple fretboard. After playing it for a while I had dirt marks all over the nice light wood finish. I'm learning blues lead guitar so doing a lot of heavy bending.

I changed the strings as the ones on it had been stiting in the shop for a while so a bit corroded. This made a difference, however even with the new strings there is still a bit soiling. The finish on the frets is a matt finish.

What the best way to avoid this and or clean it off, I hate to see my new toy looking grubby.