It is important to allow soot to dry in place for a minimum of 24 hours before attempting the initial clean-up. Here is a recipe that United Emergency Services, Inc.recommends.
4 to 6 tablespoons tri-sodium phosphate
1 cup Lysol or household chlorine bleach
1 gallon water
.Wear rubber gloves and wash the walls, rinse with clean water, and allow to dry. Commercial products are available from paint and wallpaper stores. Washable papers can be washed in the same manner as walls, work from bottom to top and avoid soaking the paper to prevent streaking. Clean ceilings last. Allow 2-3 days drying time before repainting.