To open the lower sash on your double- or single-hung window, unlock the sash and push it up.To open the upper sash on your double hung window, you will first need to unlock the lower sash. Then, pull down on the top of the upper sash to lower it. The upper sash on a single hung window does not open or close.If the window becomes difficult to raise or lower, remove any deposits - such as grease, oil or stains - that may have come in contact with the weatherstrip, apply a small amount of concentrated fabric cleaner or carpet cleaner - such as Spray-n-Wash, OxiClean Fabric Cleaner or Resolve Carpet Cleaner - to the weatherstrip. Scrub the cleaner into the weatherstrip with a toothbrush or similar applicator. Continue applying cleaner until the deposits are no longer visible. Rinse the weatherstrip with clean water, and dry with a paper towel. Pella also recommends using a dry silicone spray or a thin layer of paraffin wax such as Teflon Dry Lubricant or Gulf Wax. Do not use oily lubricants; they attract dust and grime, which will eventually restrict the window's movement. Once you have cleaned the weatherstrip, check to make sure weatherstrip is aligned properly on the sides (or jambs) of the window. To check weatherstrip alignment, tilt the sash toward you and firmly press on the weatherstrip until it is properly seated in the frame on both sides of the window. Then, tilt the window into its normal operating position and check for proper window operation.