Like any instrument, trumpets require maintenance to prevent deterioration and damage. The tuning slides allow the player to adjust the instrument so that it plays the exact pitch desired. A tuning slide that is stuck might be in tune at one time, but cannot be corrected when it is out of tune. Valves or slides that stick or are slow to move can result from a lack of lubrication or a dent inside the trumpet. Dented parts must be dealt with by a specialist, but dry slides can be removed by the musician.
Apply valve oil to the unfinished part of the tuning slide. This is the part that shows when the tuning slide is partially out. If the slide is completely closed, apply the oil to the joint between the slide and the body of the trumpet. Let sit overnight.
Put on the work gloves. Tap the tuning slide with the rawhide mallet. Hold the trumpet around the valves and grasp the tuning slide. Pull the tuning slide away from you.
Stop pulling and apply more valve oil if you see little or no movement. Tap the tuning slide again. If no movement of the slide occurs after a second application of valve oil, take the trumpet to a musical instrument repair specialist.
Clean the inside of the trumpet with the snake. Clean the tuning slide with the cotton cloth and apply slide grease on the tuning slide once removed. Slide the tuning slide in and out a few times to distribute the slide grease.
Pull and tap with a medium amount of force. It should not require all your strength to remove a stuck tuning slide. You might damage the instrument with too much force.