We recently received a call from a consumer who said that there was water leaking from the base of his faucet, from the flow to spray button on the head, the faucet would not switch from flow-to-spray, and the on-off handle sometimes stuck when turning the faucet on or off.
That is a lot of issues for one faucet, so Jim decided he needed to take a look so he scheduled an appointment.
First, he removed the aerator and found a good deal of debris – see the bottom picture.
He then removed the cartridge – the part under the handle that turns the water on and off
and mixes the hot and cold. Inside the cartridge, he found a drop of solder that must have come from the pipes where it was left when the valves were changes. The handle was sticking because of the drop of solder. When the handle was forced, it shaved the drop of solder, and the shavings continued into the faucet blocking the flow-to-spray switch.
The homeowner was not there when the 
faucet was installed, so he did not know if the valves were changed. When Jim wiped the cabinet after finishing the repair, he found the large drop of solder in the cabinet that was left behind by the install.
When a new faucet is installed, the water lines should be flushed thoroughly before the water lines are hooked up. Flushing would have removed the solder and other debris in the lines and avoided the leaks and service call.
