I'm trying to make crumpets soon (https://food52.com/recipes...), but I don't have any egg rings. I have one empty soup can with a rounded bottom, and I'd like to be able to cut it in half (or preferably thirds) so that I can use it as egg rings. I unfortunately don't have any shorter cans that I could use, and I'd rather not open up a bunch of cans and not be able to use their contents yet. How could I safely go about doing this? Thanks in advance!