A shop vac and lots of water to flush it out is what I'd do.
Then make sure to properly dry it, or it'll promote mildew/mold.
I don't know where you live, but if it's warm & dry, you might get away with just leaving all the windows open during the daytime for several days. It's too cool now during the day for that to work where I live, so a small heater or carefully placed hair dryer would have to be used. (Careful how it's positioned or your next post will be: how do I replaced the fire-gutted interior of my 2006 Aveo!