I use a wireless keyboard with my Macbook pro. After a little more than one year of use several keys started malfunctioning (not in some line). I had to press them really hard to still let them work. What i did as a solution is: (1) i turned the keyboard off with the little switch on the back (2) Held it upside down (keys facing the floor) (3) Rubbed over the keys (4) dropped it a few times on the keys from a hight of approximately 8 centimetres (3 inch?) (5) noticed that some sand, dust and little hairs ended up on the table (6) turned keyboard on again (7) After that keyboard works fine again (8) realised that my cats regularly walk over the table (and keyboard), and they do bring sand in the house ;-)