Does it really help?

it wont kill them.. it just make them go away from mattres and carpet.. but if you spray the toxin(something that used to kill mosquito) when you put the matress outside, it will kill the germ and fleas

I think, that best way to keep the carpet clean is to use the proper vacuum cleaner. But sunning the mattresses and carpets is also good for killing the micro organisms and dust mites. It's also good to air your rooms a lot or bring the carpets out in the winter, when it's cold outside (if you have such opportunity).

It's a good idea if you use a vacuum cleaner on your carpets. It is also a good idea to air it! I have found this idea how to clean your carpet Create a mixture with half vinegar and half water in a spray bottle. Use to spray carpet and furniture that may be infested with fleas. The vinegar smell will fade quickly, but this is another time you can add a few drops of essential oil for a pleasant smell. http://www.dog-health-handbook.com/vinegar-kills-fleas.html