Do whatever you feel appropriate with the contents -- feed something, throw it away, whatever -- then run a can opener around the bottom so that you have a short, squat cylinder open at both ends, peel the labels off, give 'em a quick scrub in soapy water and then bung 'em into the dishwasher on the 'Pots/Pans' setting.
If you, or a loved one, is particularly squeamish you can always substitute generic tuna cans, but cat food cans are kind of traditional.
4 english muffins
4 large eggs
4 chopped green onions
4 breakfast sausage patties
Couple of big three-finger pinches of shreddy cheese
Crack your eggs into a bowl, add your chopped green onions and the shreddy cheese, and beat well.
Toss your sausage patties onto a hot griddle and cook to your specifications.
Grease the inside of your "egg rings" with butter and place on the griddle. Spoon the egg mixture into the middle of the "egg rings" and cook until done to your satisfaction, turning once.
Split your english muffins and butter the open ends, place on griddle butter side down to toast.
Remove muffins, slide egg/onion/cheese puck in-between the muffin halves, top with a sausage patty.
LawDog's Breakfast Sandwich.