Shut off the water supply to kitchen faucet. Locate the rubber covering on the top of the handle where you press down to control the flow of water through the sprayer.
Pry off the covering with a standard screwdriver to access the switch parts underneath. You will see a round disc the size of a quarter, with a flat piece attached to a spring under the disc.
Spray the parts thoroughly with a petroleum-based lubricant. The lubricant will help dissolve mineral deposits and loosen dirt particles. Allow the lubricant to soak the parts for five to eight minutes.
Clean the parts with a can of compressed air. Insert the straw on the nozzle under the parts as much as you can and all around the cavity containing the parts.
Snap the covering back over the switch parts. Restore the water supply to the faucet, then turn on the water. Operate the sprayer for several minutes to rinse away residual lubricant.