Periodic application of lubricant to plug valves is the only recommended maintenance necessary under normal conditions. Lubrication is essential to the proper operation of the valve. The sealant, actually being the soft bearing seat of the valve, requires replacement when depleted due to flow media, operating temperatures, pressures, and frequency of cycles. Injection of sealant is done by manual injection (hand sticks) or grease gun. Valve cleaner is also available.