Are one or more keys sticking on your piano? Here are five things to try before calling a technician:
1. Check the front rail clearance (when you press the key down see how much space is in between the front rail and front of of the key). If the key rubs against it, pull back on the wood piece to see if that fixes the problem. For a permanent fix try inserting a thin piece of cardboard on each side of the keyboard.
2. Look inside to see if the piano hammers are rubbing together and not returning. This repair most likely would require a technician to tighten the hammer flanges.
3. If you have a spinet piano (spinet is no more than 37″ high off the ground) the plastic elbows under the keyboard should be checked out. Kneel down and look for spring-type latch(es) under the keyboard. Press up and pull the bottom board towards you from the top to remove it. Look at the elbows to see if they are disconnected from thin metal rods. a technician and new elbows are needed for this repair.
4. Open the top and remove the front board covering the strings (usually two latches on each side) to see if there are any pens or other objects on top of the keys that are stuck.
Remove to fix.
5. Open the top and look at the hammers while simultaneously pressing the soft pedal (left pedal) and slowly release the pedal. See if the hammers return or if they stay put. Most likely the mechanism is stuck from excess humidity. You can try to use a hairdryer gently passing it over the mechanism to dry it out. If not successful call a technician.