I saw something similiar to this on Pinterest...yes, I am addicted! I changed it up bit. After deciding to do this project, I told a few friends that I was in search of an old wooden ladder. A few days later, my friend saw not only one, but two for sale on FB. AND an old (large) milk can for $55.
First, I sanded the ladder lightly, to make sure there no little pieces of wood sticking out.