You can make your hair pin straight without using any heat by first washing it with a shampoo conditioner. Gently squeeze the moisture with a towel after patting your hair dry. Roll different sections with large rollers and wait for some hours for the hair to completely dry. Then, use a paddle brush to make it straight once you remove the rollers. Read more at http://www.ehow.com/how_5719016_dry-hair-straight-heat.html.