How do you remove starch from a fabric?

I have a hand croteched Dresser scarf. It has been starched with a product from a craft store. I've washed it over a dozen times, boiled it in water on top of the stove and it is still as stiff as a board. Any suggestions how I can remove this stiffness from the fabric.

Wash in warm water with a cup or two of vinegar added. Also use A LOT of frabric softener.

You say the product is from the craft store, in which case I wonder if maybe it's glue or sealer rather than starch? Water based glue will soak out if you leave the item in water for a few days then wash.