If I write any verse of the Qur'an for memorization purpose, then I want to dispose it, what is the proper way to do this?

For example, for memorizing a dua from the Qur'an, I write it several times, and then I want to dispose it.

Also what is the proper way to dispose any paper or materials that contain Quranic verse in general?

You can either bury it under the ground or burn it.