This is one of the easiest busy bags I've ever made and you can make so many variations it's amazing! First, I throughly cleaned the bottle top lids and let them dry. Then I placed matching round stickers on the caps. That's it. With younger toddlers you can play a simple matching game to see if they can identify which ones have the same picture. With older toddlers you can turn over the caps and play the memory game. So simple, and so fun!