White flakes on subwoofer amp ground wire?

i was wondering if anyone knows why my ground wire for my amp for my subwoofer keeps corroding. its happend twice so far. i noticed this white waxy flakey stuff on it and both ends of the ground wire had it. ive had the amp for 2 years and never had this problem. is my amp ok? the corrosion isnt very bad just dirty. and i disconnected it all. please hellppp!