The best thing is Dawn the original. They use it for bathing animals on oil spills and stuff. I got a horrible flea problem this spring. I went from bombing the house with insecticide to putting flea killing powder on the carpet and let it stay over night then vacuumed the next day. To buying a special shampoo for my cats, to using advantage on my cats. How they and I survived all those chemicals I have no idea. Well, nothing worked though. Then I purchased Dawn the original and I really lather the cats. I let it stay for 20 minutes. This included me getting on the shower with the cats and making sure that they didn't harm themselves on the process of escaping out. I lot of scratches and clawing on my body, but I was not going to have any of those fleas again. They are almost as nasty as the Honey Badger, he walks backwards by the way. I also switched their flea medication to front line and I vacuumed daily. I don't have fleas anymore. :)
For furniture and carpeting, I use Natural Defense by Sentry. It has all natural, harmless ingredients, such as peppermint oil, cinnamon oil, lemon grass oil, clove oil and thyme oil. It works great, I've been using it for years.