How to deal with the burnt edges of laser cut MDF? I'm making a Hanabi set out of laser cut MDF. When you laser MDF it has a burnt cut edge.

This can be sanded off, however the tiles are supposed to be indistinguishable from one side, and I'm concerned I'll introduce variation in the piece whilst sanding.

I'm wondering if I can just leave it there (it looks pretty nice!). I can also sand it lightly to get rid of loose burnt particles. In the long run will it slowly rub off, or is it fine as is? Also, if I decide to varnish or otherwise finish these tiles, will these edges cause problems?
After light sanding, reinforce the flat black with a little black paint, then seal the entire block in a clear coat to make it more durable.  Alternatively, replace the black with a coat of burnt umber colored paint to match the interior of the laser cut symbol (kanji?).