@derek Sealing / grain-filling first kept the dark (walnut) sanding dust out of the lighter ash pores. Also, fish glue is the traditional glue for installing metal frets in wood, and it’s very nice to clean up.
I also do most of my staining nowadays with coats of tinted shellac. It gives me more flexibility, and if I want to “back up,” I can simply take an alcohol-soaked rag and remove some shellac (and tint).
Yeah, it takes longer, but I get more control. I like that trade.