Start by slicing the tops off of the cartons with a box cutter.
Then I lined them all up in the bathtub and filled them with hot water and a splash of bleach, just to make sure they were all nice and clean and wouldn't start smelling later on.
After an hour or two, dump them all out and let them air dry overnight. They need to be very dry! Then slide two cartons together, one inside the other, to make a block.
The last step is to cover the blocks with contact paper. This holds them together and makes them look like actual blocks instead of milk cartons. I used wood-grain contact paper, but you can use whatever color or design you want! I found that it was easiest to cover the ends of the blocks first but cutting out a square a few inches larger than the carton. After centering the contact paper on the bottom of the carton, cut slits to the corners and fold up.
Then cut a piece of contact paper to wrap around the middle of your block.
And voila! A big block!
Now comes the fun part... building big towers!
Can you guess what Buddy's favorite part is?