The 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.