When stomping off your feet just won't get the dirt off, weblog This Old House recommends keeping a few pairs of unused chopsticks by the door to get them clean.
When you're not using old chopsticks to eat potato chips at your computer, keep them by your front door to clean mud, gum, or any other nastiness off your shoes before you track it around your house. Of course, if you're regularly working in the garden or kicking up dust outside, it's probably a good idea to keep that continually-dirty pair of shoes at the door, but for those unforeseen messes, it's a pretty handy tip. Hit the link for even more clever chopstick uses.
10 Uses for Chopsticks [This Old House]