A "suction floor mat," developed by Japanese company Paionia Furyokuki sucks the grime and dirt from your shoes. The dirt can then be collected and thrown away, which means you can pretty much use the mat forever. As innovative as the concept is, it retails for over $6,000. So just buy a small Dyson and keep it by the door. You'll have to do a bit more work, but look at the money you save!