If the necks are extremely grimmy, i would say 0000 steel wool followed up with wonder wipes, or wonder wipes alone my do the job. I'm sure someone with more knowledge on this type of thing will chime in though.
Jagged!
Hey, you can use the Wonder Wipes (fretboard conditioner) on your grimy neck. The grimy neck on your guitar I mean. The Fretboard Conditioner does have cleaning agents in it that will attack the dirt and grime ... as well as natural oils that will nurish and protect the neck.
my plan would be to wipe it down with some soap..diluted a lot, then mix some polish as well as some lemon oil to clean it...worse case i bring steel wool to it... after that, re finish with the gunstock oil and wax
I have had success with the wipes on a very mildly dirty fretboard. For a really dirty board, Naptha or lighter fluid will soften most grime. I generally wet a piece of cloth, (flannel works best), with the lighter fluid and gentlyrub on enough to saturate the grime. As the naptha dries, it will leave a slight haze. I then use a gentle soap, (mild dish soap or Murphy's oil soap and water) and an old tooth brush to remove the grime. Brush with the grain of the wood. Wipe clean with a damp piece of cloth. A final treatment with Wonder Wipes leaves a very nice fretboard.