Anything but metal tools!
I've used other magnets as the tool. Basically take a stack of magnets (usually how they come). Take the one you want off, pop a small piece of plastic bag on the stack, add the original magnet back on. Now you can position the magnet where it wants to go, with the piece of plastic stopping the glue going too far. Leave it set for a bit, then push down on the bag, while sliding the magnet stack off.
Not sure I have explained that too well - but hopefully you get the idea.