The New! Genuine Patriot® Dual-Layer Washable Cloth Bag provides extra filtration.  Without the Cloth Bag your machine will have poor performance and will not have a proper seal.  Cloth Bags should be changed every 2-3 years.  *Note: you can wash your Cloth bag either by hand in a sink or in a washing machine on a light cycle.  Be sure to allow 6-12 hours of drying time to pass before you place the Cloth Bag back into the machine – to prevent any possible moisture damage.