Mops are classified in two main divisions as either wet or dry mops. Wet mops are commonly used to clean kitchen and bathroom floors. They usually have sponge or cloth heads that can be put in water with a detergent or other cleaner (under the general term surfactant) and rinsed when cleaning is finished. Wet mop heads can be easily cleaned themselves, and this should be done regularly to make them efficient in cleaning and absorbing dust. Wet mops should be dried thoroughly before they are stored, and those with cotton strings that fray at the ends should be trimmed occasionally. Mop heads are replaceable when they begin to wear.
The dry mop is also called the dust mop and is characterized by a large, flat head that can be pushed easily over a floor surface. The strings making up the head pick up dust, lint, and hair as the mop glides across the floor. A swivel at the point where the mop head joins the handle allows the mop to be pushed under beds and in other places with limited access. A dry mop can be shaken outdoors to remove dust, but, if the dust clogs the mop, it should be soaked in soapy water overnight. A detachable mop head can be machine-washed. Treating the dry mop with dust mop oil after washing also preserves it and helps the dust cling to the mop head.