Shut-off valves are common in every household, especially those used to turn water on and off, sometimes called a spigot. Located throughout home plumbing fixtures and found outdoors for water mains and garden hose spigots, shut-off valves sometimes seize, especially when not used on a regular basis. Over time, unused shut-off valves build up corrosion, as well as mineral deposits due to hard water types. Freeing seized shut-off valves is often simple, but ultimately depends on the cause and whether the seized valve is firmly set.
Spray the shut-off valve with a spray lubricant. These lubricants, which are able to penetrate into the valve, help loosen it.
Loosen the bonnet nut, located at the base of the valve shaft, with an adjustable wrench. Located opposite of the valve handle, the bonnet nut is located where the shaft meets the valve body. Try to work the nut loose gradually, depending on how hard it is stuck. Don't force it, as the bonnet nut can snap the shaft.
Turn the valve handle after the bonnet nut is loose. It should operate freely. It may be necessary to tighten the bonnet nut slightly, if it leaks after loosening.
Use a torch to free the shut-off valve. If the valve is seized hard, heat the base of the shaft around the bonnet nut and valve body. While heating the area evenly, try turning the valve handle until it loosens and turns.