Just in time for spring cleaning, Consumer Reports tested eight carpet-cleaning machines from Bissell and Hoover. Prices ranged from $80 to $400. Testers also evaluated a rental machine. For comparison, they hired a professional service, too.

Testing carpet-cleaning machines is a dirty job. First, testers evenly spread a measured amount of topsoil over the carpet. Next, they spray it with water, and then use a heavy roller to press in the dirt, much like foot traffic does. Testers then vacuum the dried dirt and use a device called a colorimeter to measure the amount left on each rug.

Afterwards it is time to put the carpet-cleaning machines to work. Each one passes over the soiled area 20 times. Last step, the colorimeter measures the difference. From KUSA Channel 9 News.