It's not a matter of "10 seconds".........you have to hold it on, rotate it back and forth, and when you take it off, you have to have a visible "copper ring" around the horn base. It is that copper ring that tells you that you have left the iron on long enough. Then flick the horn covering off.........I just used the little base thingie on the bottom of the iron that was used to keep it up off of the floor or wherever you set it. The last few years I had the vet do it, as we started giving each calf lidocane around each horn. More humane for all involved and it was much less of a struggle to get the job done.