Place sheets of newspaper on the floor. Unplug the Sears vacuum cleaner's plug from the wall outlet. Upend the vacuum cleaner on the newspaper. Rotate the bristle assembly in the open mouth of the vacuum cleaner counterclockwise 10 to 15 seconds to dislodge loose dirt and unwind carpet fibers from around the brushes. Repeat the procedure, rotating the bristle assembly clockwise. Put on work gloves and pull loose fibers out from around the bristle assembly at both ends. Stand the vacuum cleaner upright and plug it back in for use. Dispose of the newspaper in the trash.
Unplug the power cord so that the Sears vacuum cleaner no longer can run. Disengage the cover plate to expose the vacuum bag. Twist the top of the bag counterclockwise to remove it from the valve socket. Pull the filter out of the socket with your hands -- grip the edge of the filter with a needle-nose pliers if it's lodged too tight to lift out by hand. Wipe off the edges of the filter with a water-moistened paper towel. Shake the filter into a trash can to remove loose dirt and other contaminants. Wipe both sides of the filter with an edge of a paper towel. Blow compressed air through the filter to further remove dirt and other contaminants. Place the filter back into the valve socket and reattach the vacuum bag. Close the cover plate and plug the power cord back into the wall outlet.
Aim a flashlight at the "Pile Height" setting at the base of the Sears vacuum cleaner so that you can see the settings that are engraved in the surface of the plastic base. Adjust the "Pile Height" lever so that its mark is against the number that most accurately reflects the depth of your carpet. If necessary, measure the depth of the carpet with a ruler.
Stand the Sears vacuum cleaner upright. Unplug the power cord from the wall outlet. Disengage the cover plate to expose the vacuum bag. Remove the bag from the valve socket and dispose of it in the trash. Clean out the valve socket with a water-moistened paper towel. Wrap double-sided tape around the eraser end of a pencil. Run a pencil inside the valve socket to loosen dust balls and other debris. Pull the pencil out. Remove any debris that has been loosened by the pencil. Place a new vacuum bag on the valve, and close the cover plate. Plug the vacuum's power cord back into the wall outlet.