Hello, I have some bumps on my fingerboard, which I thought were taken care of by the last luthier who checked out my bass. So, I'd like to take care of them myself now. I asked my luthier about this but I want to double check, my fingerboard shows streaks of lighter tan color underneath after its been sanded a bit. The luthier says that its natural, but I'm wondering, can I stain it before I seal the wood with linseed oil? I dont want to mess around with the camber. I just want to fix some intonation issues.