I have cracked eggs in the incubator right now and the ones that were fertile are developing well. I sealed them with candle wax. I took a votive candle that was in the glass holder and let it burn for a little while until there was plenty of melted wax. I took a q-tip and dipped it in the melted wax, then quickly 'painted' over the crack on the egg. Work fast, it cools really fast. If you have any extra globs, very GENTLY scrape it off just before lockdown. If your painted on wax isn't near the pipping area then I wouldn't worry about it. Hope this helps! I have a couple pics in my profile of a wax sealed egg and candling pics at day 3 and 5 of a couple cracked ones.