Hi David -

Ants yeeeccch! A natural insecticide I've found is orange oil. I use it in the kitchen and we have pets. There are lots of products out there made of orange oil for cleaning but they also kill ants on contact! I bought some stuff that's concentrate so you mix it in water then spray it on. They aren't usually marketed for killing bugs because of all the certification nonsense they'd have to go through, but the stuff really works. Only thing is it doesn't have a long residual effect so it doesn't keep on killing for days and days. You should probably try some on a test piece of varnished wood or epoxy just to be sure but I'm guessing there shouldn't be a problem.

I'm not at home right now or I could tell you the stuff I have but there's lots of it out there. Just read the label to make sure there's nothing else nasty in the bottle.