well, I made a few new cultures almost a week ago, and I've just noticed that they're developing mold. should I just toss them? luckily I have enough cultures to last me a few days, plus there's a reptile store nearby that always has fruit flies so it's not the end of the world. how can I keep the mold from spreading? and any tips on ensuring this doesn't happen again? I'm planning on doing using water/vinegar next time. any advice would be very much appreciated.