Key getting stuck

[themidnightjudge]

When I go from low C to low C#, usually the low key won't open up all the way, so when I try to go from C to C# the C# either doesn't really play or sounds airy. When I try to play the low C or C# on their own there's no problem. The key only gets stuck in transition from C to C#
My flute was knocked off a stand not too long ago, so that could be what caused the damage.
In the past I've seen keys gets stuck just because of a lack of cleaning.
So do you think It just needs to be cleaned or do you think it's damaged? And is there a specific kind of oil I can use to lubricate it?

[pied_piper]

There are a number of reasons why a key is sluggish or tends to stick:

A key may be bent slightly (due to the fall)
A spring may be too weak and need to be retensioned a bit stronger.
The key shaft might need oiling.

You can try a drop or two of oil on the key shafts to see if that cures the problem. Be careful not to use too much oil and wipe off any excess so that it does not get on the pads. Only use key oil designed for music instruments. You can get it at most music stores.

Also, you should have your flute professionally checked by a repair technician about once a year, so this might be a good reason to take it in for a checkup...