Accuracy question

[paverman]

I'm sure this has been asked and answered before, but a quick answer would be appreciated. One of my watches has just recently picked up speed, to the tune of several minutes per day. I'm suspecting that it has become magnetized (how I don't know), but I can't think of anything else that would account for such a radical change. Do magnetized watches gain or lose time?
What's the process and cost for de-magnitizing, if that's the problem?

Thanks in advance.