Residues from fabric softeners, as well as the fragrances commonly used in them, can aggravate allergies and sensitivities, and can also be hazardous in some dryers, leaving a buildup on lint screens, which can block airflow, or on moisture sensors. If you use the recommended amount of a good-quality natural detergent, you can avoid the detergent-residue buildup that causes clothes to stiffen.
Add 1/4 cup to 1 cup white vinegar to the final rinse cycle (never mix vinegar and chlorine bleach). Try 1/4 cup baking soda in the wash cycle to reduce static cling. Removing clothes from the dryer while still slightly damp or line-drying clothes will also reduce static cling.