[graham.d (OP)]

I should start by saying that this is not in order to go on a shop-lifting spree but to remove one of these tag things that was not removed by the shop assistant. I have a receipt! This is not the first time this has happened to me or one of my family so I imagine it is not uncommon. When this happened before I thought I would remove the tag myself because the shop was not close by. It was not easy. I used mechanical methods (saws, knives etc.) and eventually dismantled it to see how it worked.
 
Anyway, as it has happened again and I thought I would try more sophisticated techniques. Reading up on these things, it seems that the usual removal system is to apply a magnetic field. From my previous dismantled tag, the way the system works is that there is a slightly tapered collet containing some small ball bearings. A needle (shaped like a large tack) passes through the centre of the collet and is gripped by the ball bearings if trying to be extracted, because the balls are pulled into the narrower section of the collet. The balls are held in place with a coil spring. I know, from looking on the net, that the extractors used in shops are just powerful magnets and some are passive (not electromagnets). I think (but don't know for sure) that the way it works is that the magnets pull down the ball bearings against the spring and release the needle. However I have not been able to create sufficient magnetic field. I have some quite powerful rare earth magnets from an old disc drive but they don't seem enough. Any thoughts anyone?  Or do I have to suffer an unnecessary journey followed by the ignominy of setting off alarms going into the shop (don't know why they didn't go off on leaving)?

[turnipsock]

You need a magnet. Usually the domed part sits on the magnet and then the pin releases.

It can't really be that simple though can it, or the shoplifters would just carry a magnet wouldn't they?

[Make it Lady]

My husband had to smash one off a pair of trainers once. My son had games in the morning and his new trainers had the discs left on. It was really hard to do. I think he just used bruit force and a big hammer. The second problem is that sometimes these tags have ink inside them so that if you do try to smash them off the ink bursts over the clothes making the items useless. My sons Trainers were plain black so ink splodges were not an issue. The tag we had didn't contain ink however. Take care or take it back.

[graham.d (OP)]

You need a magnet. Usually the domed part sits on the magnet and then the pin releases.

It can't really be that simple though can it, or the shoplifters would just carry a magnet wouldn't they?

I think it is that simple for shoplifters as you can buy tag extractors for between £50 and £100. It is a cost effective investment for them.