10 ideas for what to do with used milk containers  
Make into 

1. a junior dolls house - aah, I love it!
2. containers for growing plants
3. a small watering can (Found on softgardening.com)
4. a bird feeder 
5. a purse or lunch box
6. lampshades (!)  
7. stencils
8. cut-out dolls
9. storage containers in the craft room
10. earrings - what fun!

And there are many more ideas on here: http://www.pinterest.com/search/pins/?q=milk%20containers