That’s a good idea for the inlay. It would have to be literally paper thin but it sounds doable. Maybe fill the inlay “tracks” with sawdust and glue. It would be easy to smooth with a scraper, like you said, on a large blank before slicing it up to make the pieces.
I used Danish oil to finish it. Polyurethane would never stand up to the kind of abuse this box takes. Even if I could somehow keep it from peeling off, it would be scratched up very badly. Anyway, there’s so much resin in this wood that it is sort of naturally sealed. (It used to be pier decking.) The oil just keeps the outside from graying. I used teak oil on the first one and it held up nicely, even getting darker over time. Very chocolatey in color. I’m sure some of the dark came from jingling against my brass Zippo. I noticed smudging early on from oxidization against the brass. After a while that went away. I think whatever chemical process between the two faded out over time.
I only smoke outside the house, so at home I leave it on a little table under an awning out back. It doesn’t get rained on unless it’s blowing hard, which happens a couple of times a month. But it sits out there overnight no matter the weather and often during the morning it takes the heat of the sun. Then, of course, it goes in my pocket whenever I leave the house and gets exposed to all the elements I do, including surf fishing, which is by far the most abusive, having been literally dunked a few times in salt water, but takes salt spray at least every other outing. I have to say, this polyurethane glue is pretty amazing stuff to hold up as well as it did against the elements. I have 2 pockets in my surf jacket and only one is waterproof so that one stores my fancy electronic car keys. Modern car keys are so bad. They should be 100% waterproof but they’re not. So old reliable Zippo and ekki box go into the flap pocket to take on the rain and salt spray while I’m standing on a rock waiting on that big girl to take my bait and praying I don’t get washed off into the current. Haha… This kind of fishing is not for the timid. I almost got washed off a couple of days ago while trying to bring in a fish. The fish got away and I ran away after that. LOL
Losing fingers since 1969