It's mixed with sweat an d it's EVERYWHERE!!!!!!!!!!!!!
Step 1: Vacuum up as much of the chalk as possible, being careful not to spread the stain from the chalk further.
Step 2: Mix a solution of two cups cool water and one tablespoondishwashing liquid.
Step 3: Using this solution, sponge the stain from the chalk with a clean white cloth.
Step 4: Next, blot at the stain until the liquid is absorbed.
Step 5: Repeat steps 3-4 until the stain is removed from the upholstery.
Step 6: Now that the stain is removed you should get plain cold water and a new white cloth and sponge the area to remove the cleaning solution, and then blot dry.
Hint: Be sure to get the upholstery only as wet as necessary to remove the stain from the chalk.
If this does not work, an alternative is to use a dry cleaning solvent on the upholstery until the stain disappears.