Depending on your design…
Char can be made to work for you. Lean into it, and look at it this way:
Very lightly sanded and oiled up, char becomes pretty stable. You can get really black edges to your piece that won’t “bleed” and can be used as a design element. You might not need to lightly sand it either, it’s dependent on the species.
Finger joints get a black outline and can be decorative. You can do lots with finger joints to make them visually interesting, check out @geek2nurse did here with dark edges and fingers:
Great work all around on that, but the fingers just make it pop.
Likewise, I did a study of variations on finger joints:
Beyond that, if you really hate the char, you can overcut your pieces. Make your finger joints a bit too long (0.02" should be plenty), and sand them flush. You’ll end up with a gorgeous understated fingerjoint where the zebrawood can be front and center. If it’s an open topped box, assemble it first, then you can sand the edges clean on the top and bottom. No one will ever know your char secret.
I guess all I’m saying is that char itself isn’t a death toll. If you can get it to cut reliably and figure out your kerf compensation, you can use really charred woods to get great results.
Here’s a practical result:
Purpleheart chars a lot and can be finicky to cut. With the sanding techniques I mentioned, you can get results like this:
Looking closely, you can see that the char shows as thin black outlines on my finger joints. There is also a bit in that third picture (with the out-of-focus dice) if you look at the edge, you can see a bit of char I didn’t sand off, it’s a dark section of the wood right near the corner and another small section on the “cross piece” that divides the 2 sections of the tray. Ultimately I decided I liked the “antiquing” effect that this had, and left it.
Trust me, the recipient of this tray was astounded and only sees the gorgeous purple color. Anything you make with zebrawood will be the same, just stunning. Sand it as much as you can stand to really highlight the wood and make it a pleasure to touch (600+ grit final finish will make an impression), and get ready for the flood of compliments. 