Sizing is a substance that fabric manufacturers and clothing distributors use to make fabric hang better on the rack or on the bolt. While this does give fabric material a better hang, it also makes it stiff and starchy to wear. Before sewing the fabric or wearing the clothes, make sure you soften the fabric by removing the sizing. This allows you to wear the clothing more comfortably, and if you are sewing with the fabric, it allows you to cut it more accurately.
Cut any tags away from the clothing or fabric.
Inspect the care instructions. If the care instructions say that the garment should be dry-cleaned only, take it to the dry cleaner. After one cleaning, it will come back softened for wear.
Place the fabric or clothing in a washer.
Pour in the detergent as you normally would.
Add 1 cup of white vinegar to the load.
Wash and dry as you normally would. When the load comes out of the dryer, the stiff and starchy feeling is gone.
Fill the sink with warm water.
Remove all tags from the clothing or fabric.
Soak the item in the warm water.
Add a quarter-sized amount of washing powder.
Add ¼ cup of white vinegar.
Wash the fabric by hand, agitating it in the water for at least three minutes.
Rinse the fabric thoroughly.
Hang the fabric up to dry.