We use pickling salt at our house. I sow it as I do fertilizer in the garden and just leave it. It will work it's way down to the bottom of the carpet as you walk on it. I leave it on there all the time and my carpet is still OK, but I don't know about yours. You can also use it on bare floors. Sprinkle it on and then take a broom and try to work it into the minute cracks in flooring and under the baseboard. The salt nicks the carapace of the flea and the flea will dehydrate, of course killing them. It also does the flea eggs the same way. So far we are having good luck with it, but then the animals come in and out so they are still bringing fleas in, but they are a lot better and I think after the first hard freeze we'll be OK.
