If you want to have some stains removed from your carpet then here are some neat tricks on how you can do it:
1. Use Doormats
Interior doormats can only stop dirt from being tracked inside if they’re clean. If the care tag allows, you can toss mats into the washer and dryer — use the gentle cycle on warm and tumble-dry low. Otherwise, use a vacuum. Go over the front of the mat, flip it over, and then vacuum the back, even if it’s rubber or plastic (this loosens any embedded dirt). Then flip the mat again, and vacuum up the grit that came out. (Just you wait: It’ll be no small amount.) For a quick refresh, take the mat outside for a good shaking, beating it with your hand or a stick a few times on each side.
Source: http://www.goodhousekeeping.com/home/cleaning/tips/a24228/remove-set-stains-carpeting/
2. Spray Hydrogen Peroxide
Simply place the hydrogen peroxide on a spray bottle. Spray it on the old stain. Saturate the stain if you must to loosen up the stain’s particles. Let it sit for about 10-15 minutes. You will need a little bit of elbow grease now. Use a stiff brush to work on the stain to help it loosen up some more. Then use a steam vac to suck up the peroxide mixture from the carpet. You may also use towels and cloths to absorb the peroxide. Your carpet should hopefully look clean and stain-free.
Source: http://cleaning.lovetoknow.com/How_to_Remove_Old_Stains_From_Carpeting
3. Use a Tough Cleaning Agent
Spray any remaining stain with a cleaning agent. Use a store-bought formula or our homemade stain remover. Tips for removing specific stains are listed below. Take care not to over-wet the stain, which can damage the backing. Let it sit for 10 minutes.
Source: http://www.bhg.com/homekeeping/house-cleaning/surface/carpet-stains-and-how-to-remove-them/
By following the tips that were mentioned above, you are sure to make your carpet free of stains and make it look like brand new.