If you have a modeling clay stain on your clothes, it can be very difficult to get out. The first thing you need to do is read the tag on the garment that you are going to wash. Be sure that it allows you to follow some of these cleaning methods before performing any cleaning steps.
Using a bucket of warm water, mix in some all color bleach powder with your water. Soak the fabric overnight. You should realize that some colors will fade a bit when they are soaked in bleach, even all fabric bleach but soaking the entire garment at least it will all be the same.
Before laundering, rub some liquid detergent on the modeling clay stain and scrub it in a bit with your fingers. The stain should be very light or gone at this point. Wash and recheck. Soak and rescrub as needed until the stain is gone.
Donít use regular bleach unless you are sure that the colors are not going to bleed with the fabric turning white.
If your modeling clay stain remains in the fabric look for a color stripper in your home cleaning section or in the grocery store. The stripper is going to take all the coloring out of your fabric and then you can re dye the fabric the color of your choice.