what to do with knots in cutting boards?

If it were me, I would fill the knot holes with a mixture of 5-minute epoxy and fine sanding sawdust. Fill the holes and leave them just proud of the surface where they can be scraped and sanded down once cured. I use this fix for almost all of my knot problems.

-- Do or do not...there is no try - Master Yoda

Another vote for epoxy here.

-- Dan Lyke, Petaluma California, http://www.flutterby.net/User:DanLyke

Depending on the size, drill out the knot with a forstner bit, then glue in a plug from the same specie. I haven’t needed to do this, but it seems like it would work. Just a thought.

-- Art