I first came across these astroturf Clean Machine door mats at Kmart.  They caught my eye, because the Taupe color was really perfect for blending in with the weathered grey color of the decks at my house on Fire Island.  They’re not elegant, but boy, do they work – perfect for keeping that wintery mix from getting tracked into your home. Not only is the Astroturf remarkably effective at wiping your shoes clean as you walk on it, but the dirt (or sand, in my case) drops deep into the mat, where it’s held until you shake or hose it clean.  They withstand freezing, and while they’re not recommended for wood decks exposed to significant sunlight, I’ve had no trouble with the one on my sunny deck.  They come a range of colors and sizes, and are available from Amazon.com with Prime shipping.