After receiving the Eucharist, if there are any elements that you did not take (for example, if you were allergic to grape juice and did not drink it), take them outside and put them in the ground. Do not feed them to pets. This is a way of showing the appropriate honor and respect to the elements that have been consecrated as Jesus's body and blood. Then, rinse your cup and pour the water outside. The plastic cup and cover can be thrown in the trash after you have rinsed them.