"OK Mrs. Jones, we are going to spot dye this bleach area in your hall. It may not be perfect but it will be better and the cost is pretty low. But wait! That's not all, the next time we clean it will have to be done all over again."
/quote]
Presumably, the crayon, or pastels as Tony used, become colorfast upon steaming with an iron.
I found this interesting; maybe a pastel fixative would be a better method (from googling pastels):
"Pastels are sticks of ground pigment mixed with chalk and gum or oil, then shaped into drawing sticks. Pastels cannot be mixed on a palette like paints, but are mixed on the paper by overlaying or blending.
Pastel Fixative
Pastel paintings must be fixed to prevent smudging. Fixative is a resin dissolved in spirits; when you apply it the spirits evaporate leaving the resin to hold the pastel pigment in place. Fixative can be bought as an aerosol or in liquid form, which must be applied with an atomizer, not painted on. Always use fixative in a well-ventilated area."