Two pennies can be considered the same — both are pennies, just as two elephants can be considered the same, as both are elephants. Despite the vast difference between pennies and elephants, we easily notice the common relation of sameness that holds for both pairs. Analogical ability — the ability to see common relations between objects, events or ideas — is a key skill that underlies human intelligence and differentiates humans from other apes.
A point of note, your kidneys and liver do a great job of “detoxing” the body. There is no special thing you need to do or buy to help it along; if you really want to give your liver a high five for being awesome, just drink in moderation.