Sled runners are glide waxed the entire length of the base.
Glide waxing both protects the runners and adopts the base to the conditions. In order to maximize the durability of glide wax, the wax is heated into the base using an iron with the excess wax scraped off. A gas torch often produces too much heat. To wax at race sites I therefore got an inexpensive traveling iron and an inverter which allows me to power the iron using my truck's 12V battery. Spray a good amount of citrus wax remover onto your base and soak for a couple of minutes.