Two comments first why the hell would anyone put a magnet on a guitar pickup in the first place?
Then secondly I'm not buying it - why would putting a magnetic on a guitar pickup ruin it? a Tele don't have active pickups so you could not have damaged anything electronic so what would it damage? It won't play right with a magnet there that's for dam sure but as soon as you removed the magnets the guitar should play fine again. The only way you could damage the pickup is if you magnetized the metal case by leaving a really strong magnet there long enough to magnetize some metal component and at worse you would have to degauss the pickup. Or if you had a really strong magnet like and electromagnet that could demagnetize the pickups own magnets but that would take a pretty good sized magnet. More likely you magnetized the strings which can happen easily but that's a simple fix change the strings. I know that because if you fool around enough with a ebow or other electronic magnetic toy you magnetize the strings, not ruin the pickup.
Ive kept stack's of telecaster pickups in a shoe box stuck together for years and they work just fine. So somebody please explain how they think this could ruin a passive pickup. I was sure enough about this I just stuck a magnet onto my tele and played it as suspect sounded like total crap with the field distorted pulled the magnet off and the guitar was fine no issue at all, somebody need to send this to the Mythbusters TV show. Ive found that unless you try taking them apart of you damage the windings in some way guitar pickups are tough. Ive literally found old ones in luthiers junk drawers covered in all sorts of crap with screws and other stuff stuck all over the megnets and it the cases are in tact pull the stuff off clean em up and they work fine usually when a pickup is damaged it's because somebody was trying to work on it or something like that.