Here's what I do:
1. Have one of these.
2. Fill up spray bottle with leftover vodka from vodka martini.
3. If still seeing straight, fill remainder with water.
4. If costume still smells,
and
5. Procede to not care if costume is stinky or dirty or not and lay down.
Seriously though, I use equal parts vodka and water, but I have also used straight vodka as well.