What scott says is the recommended approach. Just lightly coat the screens with vegetable oil and put them in the oven at 425 degrees F for about 15 to 20 minutes. Any higher than 425 degrees might reach the flash point of the oil. Once the screens have been seasoned, they should not be allowed to soak in water or else the seasoning can come off and have to be re-seasoned again. If the screens have to be washed, the recommended approach is to dip the screens in hot soapy water, scrub lightly with a soft bristle brush, rinse, sanitize, and run them through the oven to dry. Over time, the screens can get carbon buildup. A small amount is actually desirable and becomes part of the seasoning of the screen. But if the carbon buildup becomes excessive, what some operators do is to run the screens through their ovens at high temperatures and rap them against a hard surface, which shakes the carbon loose. At some point it just becomes easier to replace the screens since they are fairly cheap to begin with.
A dough on the wet side can still stick to a seasoned screen. So, it is wise to have all the ingredients prepared and ready when it comes time to dress the pizza, and work fast.