Wring water out of the insoles and inner boot material, then jam dry newspaper into the boots to soak up as much residual moisture as possible.
Cut a 4-foot length of 4-inch PVC pipe in half at a 45-degree angle, so that you have a pair of 2-foot-long pipes with one end square and the other angled.
Roll the waders inside out so they stand about 2 feet tall. Remove the newspaper. Insert a pipe in each boot, pushing the angled end into the toe.
Turn the entire contraption upside down over a floor heat register. The rising air dries the main part of the boot, as the pipe funnels hot air into the recesses of the boot toe.