I use wooden spring pegs. I used to have some plastic ones, which had a vice-like grip, but unfortunately they only gripped the clothes. They allowed the clothes to slide along the lines, so, unless I cleaned the washing lines religiously every time i pegged out the laundry, grubby marks appeared on the washing. However, those plastic pegs are absolutely brilliant at holding my fruit nets together when I have to keep the birds off my fruit crops.