Plug the Hoover Mach 4 vacuum cleaner into a power supply. Push down on the foot pedal to lower the handle to the desired cleaning height.
Turn the "Carpet Height Adjustment" dial to the desired position. The lowest setting is appropriate for all carpet types, while the higher settings are best for deep pile carpet.
Turn the power switch to "On" and move the vacuum cleaner in a steady back and forth motion over the carpet area to be cleaned.
Turn the power switch to "Off" and unplug the vacuum cleaner when finished. Press the "Dirt Cup Release Button" on top of the dirt cup and turn the cup while pulling it out to remove. Hold the dirt cup over a waste container and push down on the "Release Button" to empty.
Turn the filter assembly from the top of the dirt cup. Tap the filter over a waste container or use the vacuum cleaner's brush tool to brush away the lint and dirt.
Locate the secondary filter behind the dirt cup housing. Pull the filter frame out from the vacuum and remove the black foam filter from the housing. Wash with cold water and liquid dish soap. Rinse well, air dry and replace in the filter frame. Slide the filter tabs into the slots on the vacuum.
Close the dirt cup lid and pivot the dirt cup back onto the vacuum cleaner until it clicks into place. Store the vacuum in a cool, dry location.