I remember years ago I had a vacuum cleaner that had a compartment for little air freshener pellets in the hardware of the machine itself. Didn't really use them much. If they are still available maybe drop one in the bag when you change it? Or, instead of the powders on the carpet, febreeze or some other such spray? I personally was never fond of the powdery things for the carpets - just seemed to trap the dirt even more to me.