This clever hack is dependent on you living in a sub-freezing locale with an abundance of snow, but if you meet those requirements you can give your rugs a thorough deep cleaning using nothing more than snow.
Over at the home-centric blog Re-Nest they highlight how you can clean a wool rug—no word on whether it would work with synthetic fibers—using freezing temperatures and powdery snow.
You take the rug outside and leave it there, draped over something, to acclimate it to the cold temperatures. Once you've left it outside you toss it down on the snow, beat it with a broom, flip it over and beat it again, and then sweep off all the snow before bringing it back inside. The freezing temperatures and the rubbing of the snow against the rug helps loosen dirt and kill bacteria.
Check out the article at the link below for more photos, detailed instructions, and additional clever cleaning tips. Have a tip of your own to share? Let's hear about it in the comments.