First, preheat the oven to 375 degrees. After the oven reaches 375 degrees, spread the cereal in a single layer on a cookie pan.
It is important to be sure that the cereal is spread thinly on the pan. If the cereal is clustered on the pan, the underlayer of cereal will not crispen properly. If you have a lot of cereal to re-crisp, you may need to use two or more cookie pans.
After about 2-3 minutes, open the oven and gently shake the cookie pan and slightly to rearrange the cereal. At this time, also check to make sure that the cereal is not browning in any way.
