Why does my trackpad button appear sticky or non-responsive?

My trackpad button has recently started responding only sporadically. I actually thought the hard drive was about to fail, because I thought it was freezing, but discovered that it was just that the trackpad button press wasn't actually being registered by the machine. Using a bluetooth mouse, it's perfect.

I can continue using the mouse, but I'd obviously like the trackpad to work. Anyway I can take it apart and clean it or check it? I've seen the tri-wing screws; they give me the heebie-jeebies...!

Yeah, I checked the battery and it's flush. There's no bulge or anything in it. Probably still needs to be changed, but don't think it's the issue with the trackpad.

@remacberlin, I think you're right, it probably just needs a good clean but I've no idea how to get at it! I'll see about getting one of those tri-wing screwdrivers.