How to remove iron-on patches?

I would try using a warm iron to soften the adhesive and pulling it off gently. I have not attempted this. They usually come off when I do not want them to.

Carefully choose the ironing settings: it should be preheated to the hottest temperature the material can handle, but without a steam. Press the iron down over the patch for about 15 seconds, then peel the patch from the base material. It is better to use some gloves/pliers because the material and the patch can be very hot. Detailed instructions on removing patches you can find here -

I've had some success removing them by ironing them and pulling them off while they're still hot. Doesn't get rid of the glue residue, though.