Originally Posted by Surf City Garage
You are going to want some sort of forced air to blow out the cracks so that you don't get residual wash crying from your car.
Check out the Sidekick by Metrovac. They can be found on Amazon.
lol nice attempt at trying to sell me something :P
A cheaper and easier method I found - open your trunk and let the water all drain out (it gets trapped in the cracks during washing and runs down the back)