When sheets and other linens are first packaged, they are often treated with chemicals to keep them wrinkle-free through the shipping process until the sheets are purchased. This can cause the new sheets to feel very stiff to the touch. Washing them does not always solve the problem. But there is a simple technique you can follow using white vinegar that will strip excess stiffening agents from the sheets and allow them to come out nice and soft.
Place the stiff sheets into your washing machine and add exactly 1/2 the amount of washing powder you would normally use. The regular amount of detergent can cause even more build up, leaving your new sheets stiff and uncomfortable.
Pour 1 cup of white vinegar into the washing machine during the rinse cycle. The vinegar will strip away the chemicals that cause stiff sheets.
Place the washed sheets into the dryer after the cycle has finished and add two dryer sheets. Tumble dry the sheets for a soft finish.