okc2010commander; I use a rubber mat I got from WalMart on top of the box. It's loose so I can lay it over the key/pull on top.
and take out to clean. I wanted something easy to clean and would not hold water or smell.

Oh the beverage retainment system is made from an oversized cargo new and bungee straps.
I put 3 screws thru the bottom strap into the plastic to keep rolling cans in check.