The ink does not absorb into those materials, you can wipe it off pretty easily. I taped off the rest of the guitar to be safe, but found that it was not that hard to keep most of the ink on the wood and wipe it off the other parts. Just use a little, it does not need to to drip and run on there, just enough to soak into the wood.How careful do you have to be to not stain the fret markers and binding?