Use tweezers to remove ones with fungus, check a couple times a day and remove them as you see them, do not leave them in.
Cory eggs darken if fertile but turn white if infertile. But if theyre albino babies, it may be harder to see as they may not darken. So i would opt to leave them all unless they fungus, remove them at day 7 at the latest (they take 3-5 days to hatch)