I just wanted to share this with the community. i bought some locking backs for my pins off ebay, and i tried one on my 15th anniversary pin (in hind sight not the best one to try it on) well it got stuck and in trying to remove it (yes i was following the instruction for removal) i broke the pin off.
luckily i have 2 of the 15th anniversary pins but i was hoping to use one to trade. I just wanted to let everyone know to be careful because apparently those pins can snap off fairly easily. Also to let everyone know there are now only 1999 of them in existence.