Pick tomatilloes when they're still green for use in Mexican dishes. If you wait until the husk turns brown and they fall off the plant, they're too sweet for use in salsas or enchilada sauces. Some people use the ripe yellow ones in salads or worse, pies. Just wait until they're large enough to mess with. If they're pearl-sized, it will take you forever to husk and wash them. The sticky stuff under the husk washes right off, and that's all you have to do to them. I food process them and saute them if I plan on freezing them. Margaret