Wow, I had no idea this could happen in a vivarium! My only experience has been with aquarium snails! It's great that you were able to clean everything in there. I'm not like an expert on what's safe to use and whatnot but I've heard that vinegar is safe to use in a vivarium? I would think that spraying a diluted vinegar solution on it and letting it sit and then rinsing it and repeating would probably kill leftover eggs since vinegar is so acidic. But like I said, I would do it a couple times just to make sure they're dead. Snails are resilient little things!