To remove foundation stains blot the stain with a clean cloth or paper towel to absorb as much of the foundation as possible.
Don't rub the foundation stain as it can push the foundation stain in further into the fabric and make it harder to remove.
After you blot the foundation stain with the paper towel or cloth, rinse the stained area off with some cold water to loosen the foundation from the fabric.
Next apply a small amount of laundry detergent or dish soap to the foundation stain and gently work it into the fabric or clothing with a cloth or a brush.
Then you can try to wash the fabric or clothing in the washing machine with laundry detergent and you can even use a commercial stain removal.
If the foundation stain is still stubborn you can also use some baking soda to pre-treat the foundation stain and let it sit for a couple of minutes and then brush off the excess of the baking soda and wash as usual.
You can also use some foaming shaving cream to help remove the foundation stain, let it sit and them wash the fabric or clothing.
Dabbing a small amount of rubbing alcohol on the foundation stain and allowing it to sit and then washing the fabric or clothing can help to remove foundation stains.
If the foundation stain still remains after washing the fabric or clothing, you can also try soaking the fabric or clothing in some oxygen based bleach such as oxiclean and water for several hours and then wash as normal.