For regular, everyday carpet cleaning, a traditional push vacuum is the best tool for the job. But if you have tough spots and stains, a wet/dry shop vac might be just what to need to get rid of them once and for all. Substituting your shop vac for a professional carpet steaming and cleaning machine can save you money on machine rental fees or if you're thinking of buying your own.
Plug in your shop vac somewhere near the stain you want to clean.
Dampen the stained area with a little water, then work in a carpet-safe spot cleaning detergent. You should follow the specific instructions on whatever product you choose to use, but in general, the detergent should be scrubbed into the stained area using a soft-bristled scrub brush.
Attach a fine slotted attachment to the end of the shop vac hose and vacuum up the water and soap.
Dampen the area again and swish the area around with a paper towel if necessary to kick up any suds that remain.
Vacuum the area again until most of the moisture has been sucked out.
Repeat Steps 2 through 5 as needed to clean the stain completely, then allow the area to air dry.