The wet bags have zip tops and of course- they're machine washable. They're actually made to last for quite some time. They also sell Hanging Pail Wet Bags that you could use instead of a more traditional diaper pal. We're wondering exactly how they compare in terms of sealing in that smell. Another great use for the Wet Bag- a place to toss wet swimsuits or towels in the summer when you're on the go.