Nothing. I own one. Drive it over here. Last thing I used it on was lilpooky'* 96 Neon that had the same problem from a leaky window seal.
Some DIY car washes actually have them near the vacuums. Or you can rent a rug doctor from your local grocery store, but make sure you have a hose attachment setup.
Otherwise, just find someone that owns one you can borrow. Alot of people have the Green Machine or a Bissel from Costco these days.
Solved Kim'* smelly Neon problem in short order (and fixed the window).