First question to you is do you live in a "stand-alone" house or do you share walls with another house or apartment? The fleas spend only a tiny percentage of time on the animals, the rest is in the environment (in the house, outside) and for every one you see on your cats, there are about 8 in the environment. If you have shared walls with another house, it is much more difficult to rid the house of fleas (but you need to be diligent about putting a good quality flea product on your cats). If you have mice in your house, it is also difficult to get rid of the fleas. If you don't have mice, don't share walls, the fleas probably came in on their own or on you and your family members. It's fine to wash the clothes and beds but the fleas jump and move a lot so whether they had contact with your cats makes no difference. The flea products on the market now are so good that there is no reason that you shouldn't be able to get control of the situation. Please check with your Veterinarian or at least call the clinic to make sure what you are using is really safe. Stay away from Hartz products or the cheaper, store brand products. Try frontline, revolution, advantage and better products like that for on the cats. As far as for in the house, please make sure to check with your Veterinarian what to use and how to use it so it really is safe for your whole family (humans and cats). Fleas love heat and humidity and this spring has been hot and wet so perfect flea weather!
Good luck!