While browsing REI I noticed a variety of stuff sacks for backpacking like this one http://www.rei.com/product/766293. What I was wondering is if it would work for keeping my dirty sneakers from smelling up my luggage. Right now I take a plastic bag and wrap my sneakers in them and then pack them into my bag. This works but it's not really green because of the plastic bag. These stuff sacks say they can keep water out so would that mean they keep the smell in? I'm not a backpacker so this isn't something I'm familiar with.