Being curious, I looked up what might cause mold on incubating eggs. Didn't really find that answer, except too high of humidity. What I did find, from a snake forum was a couple solutions people have used with success. Have you ever tried anything besides wiping them off? Which they said would spread the mold? Here is what they mentioned. (Dabbing with listerine on a cotton tip) and (sprinkling tinea powder on the eggs). I have no idea what the powder is, thought you might. Again, these were for snake eggs. Maybe others might have heard of this or used it themselves. Be interesting to know if either would work for tort eggs.