Wash your clothes right away. As in--don't drive or fly home. Go to the nearest laundromat immediately. The longer you let your clothing sit around, the more stale the playa dust gets, and it can get pretty icky. Add a splash of white vinegar to your laundry (in addition to your regular detergent) to cut through and break down the alkaline playa dust. If you wear leather boots, clean them thoroughly with a rag soaked in a vinegar and water solution, then rub them down with mink oil. Finally, take the clothes you use exclusively for Burning Man, and put them in labeled tubs so you can get at them easily when August rolls around again. Oh, and definitely wash that wig.
The key here is to stop idling around, buckling down, and getting it done. If you can head directly to a laundromat, your home will love you for it. Take all your personal belongings out of your vehicle, clean it (using a vinegar-based cleaning solution helps), organize it, and repack it. If you’re really organized, make lists of what’s in each container. Take note of what you need to replace and what you had excess of. This is a great project to work on while you're waiting for the loads of laundry to cycle! Professional Burners learn over the years how to organize their stuff so they can practically grab a few totes, toss them in the car, buy some beer, and head to the playa. Practically.