How can I fix a sticking key on an upright piano?

Very intricate instruments and it could be a number of parts that are causing this. Has this happened recently or has it been a long term problem? It could just be the weather changing outside (ie: if it's turned damp outside). It might be somedirt/dust stuck down the side of the key but to be honest it's something a tuner/repairer needs to look at because as I say they are very intricate and complex mechanical machines and it could be any number of parts which are causing the problem. I'd check for dirt/dust/piece of paper down side of the key and if no joy get a tuner/repairer in.
E

E
April 2009

first find the problem
draw back the hammer of that key and release
if action free cause is in key mech.
if not cause is in action
proceed with extreme caution
Try piano lube on action pivots

check for interference between parts
Kids drop coins, tiddly winks, jam etc which easily lodge in dodgy crevices

Asanewt
January 2009