You pry the tab up to a 45 degree angle. Then insert a finger. While firmly holding the can with one hand, pull back with the other hand on the tab, the can should open smoothly. At the very end there is a chance the lid will spring off the can, so you should use less pressure when the lid is almost totally detached.
If you have trouble getting under the tab (like you just cut your fingernails), use any flat thing to give you leverage, a spoon, toothpick, screwdriver, etc
I use these all the time, no issues.
You pry the tab up to a 45 degree angle. Then insert a finger. While firmly holding the can with one hand, pull back with the other hand on the tab, the can should open smoothly. At the very end there is a chance the lid will spring off the can, so you should use less pressure when the lid is almost totally detached.
If you have trouble getting under the tab (like you just cut your fingernails), use any flat thing to give you leverage, a spoon, toothpick, screwdriver, etc