I have a wireless keyboard that has been used for less than 3 years, which is Microsoft, one day it didn't work at all, I have plugged and unplugged the receiver a lot of times but it still doesn't work, however, the separate keypad works perfectly. so it suggests that the receiver is good. I then found that one pole of the battery is not shiny, while another pole is shiny like new (It requires two AAA batteries) I don't really understand. I always use batteries of the same brand, one battery chipped, I think it's the reason that polluted the pole (Is it the possible reason?). Now , how can I clean up the rusted pole of the battery? Can I wipe it with 75% Alcohol? Is it safe? I know that 90% is better for electronics but it's not available in most of the pharmacies nearby. Will the alcohol go into the inner of the keyboard and cause danger?