Why does my car have streaks after drying with a towel?

Towel streaks usually come from residue rather than the towel itself: too much drying aid or detail spray, shampoo left on the paint, fabric softener in the towel or a towel that is already saturated. Hot panels make streaking worse because products flash before they spread evenly. Use a clean, absorbent towel, a light mist of drying aid if any, and a second dry towel to buff the panel if streaks remain.