Method and system are disclosed for operating wagering game terminals where each terminal contributes an award to an award pool. The present invention has its purpose to constantly set the amount of purge of nitrogen for inducing the waste gas to discharge while increasing a temperature of the waste gas so that dust of the waste gas is not accumulated on the inner wall of a pipe, and prevent an accident such as a burn from occurring in workers. The objects are further preferably cached with an LRU process.