X button is really hard to press and doesn't get back to place.

I have an Xbox 360 wireless controller that I haven’t used in a long time (probably like 5 years ago) and now that I wanted to use it back, the X button is really stiff and kind of locks in place if its not pressed regullarly.

It’s needed to aply quite a bit of force to get the button down and when it finally gets pressed down it gets kind of a mushy feel and it doesn’t gets back on top, in place, until a couple seconds but it works perfectly fine, when it reaches the bottom the console detects it properly. I think it might be just the mechanism of the button being dirty or stuck by the lack of usage but I dont really know.

Does any one have faced the same problem and know what is it or how to solve it?

Thank you!!!!