My 9C was among the first shipment delivered to the US. I've had it since December 2001 and I've not had any problem with the vacuum metallized plating on the case. It actually looks close to new.

However, I've seen another fellow pilot who had this problem, however, on a radio perhaps a little over 1 year old. On his, it seems to have been aggravated by lots of fuel always on his fingers (he flies heli's). I am really careful to keep mine clean, I always clean oil/fuel off my hands before I fly, and store the radio is a carrying case when it is not in use.