The maple fretboard of my Sterling had two marks from string bending at the store before I got it. I lightly sanded the two spots with fine sandpaper and applied some leftover Warwick wax. Looks perfect
What type of marks? The maple neck on my P/J has what looks like a ground in black smudge about an inch by one-half inch. I've lemon oiled it, etc., but it won't go away and looks like axle grease.
It needs to go. What grit sandpaper did you use? Do you think the Birchwood-Casey wax would work in lieu of Warwick wax? How many coats of wax did you apply?