my shift button is slowly becoming unresponsive...help?

i noticed a while ago the shift button on my xl wouldnt always register when i pressed it. its starting to get worse and i either have to press down really hard or try a million times before it will key in. i know the number keys on the xl are especially cheap build and seem prone to failure...what should i do to fix this? is it a matter of opening up and putting contact cleaner on the button on the board or am i going to have have to replace the button sensor with a new one?

does anyone know where i can find this replacement tact switch? i dont think mine is going to be working much longer. damn xl plastic buttons...

best bet is ebay. You can buy them from MPCstuff but dollar for dollar its way smarter to buy them in bulk.

Open up your mpc (you have to at some point anyway) and check to see if it is just the plastic. This has happened to me before where the actual switch was fine but the plastic wore out. Saves you some work if it is just that. Due to the nature of it loosing it's responsiveness, it leads me to believe it may be simpler than replacing the switch (or it has been for me in the past atleast). Opening it up will let you know what is really going on reguardless.