Following the suggestions we've outlined above should help you eliminate foul odors. If they don't solve the problem, it's time to call in the pros. For example, if your air conditioner continues to stink up the room after you've changed the air filter and cleaned the other components, there may be a serious underlying issue. Similarly, keeping water in your S-trap and replacing bad plugs should fix your sewer gas problem, but a cracked or leaking pipe will require professional assistance.