Well the environment on the inside of a clarinet, covered with spit, is certainly much more demanding than a fretboard - so I imagine bore oil should work just fine. I doubt it will make a difference, as just about any product will do the job, as long as you use it regularly and not too often (at most with every string change, or perhaps just once a year). As for whether plant based or mineral oil based treatments are better, that argument has been going on forever in the guitar world, with no winner yet.I have been using Roche-Thomas premium bore oil on ukulele fretboards when changing strings. My understanding is that it is superior to lemon oil in conditioning fretboards. It is plant based and not mineral oil. Any thoughts?