One of our parents donated a bag full of plastic bottles to our school. In the bag were six small Pom juice bottles. I have wanted to make bubble bottles for about a month now and these seemed perfect for them. After rinsing them out, I put about a fourth-cup of water, a bit of liquid water color (you could also use food coloring), and a squeeze of dish soap into each bottle. I hot-glued the lids on so that we wouldn't have colored bubbles everywhere.
The children also used these in the dramatic play area as juice bottles. They pretended to pour the juice into cups and bowls.