The ruling on throwing used handkerchiefs into the shelves of the Qur'an

Question:
May Allah reward you. This questioner, Abu Ahmad, says: We observe, Shaykh Salih, in the mosques and among some of the worshippers (may Allah guide them), that after using a handkerchief, they place it under the prayer bench or the pillar, or place the used handkerchief on the shelf of the mushaf. Do you have a word on this?

Answer:
It is not permissible to throw filth and used handkerchiefs in the mosque. This is a disrespect to the mosque, and it is a sin, as the Messenger (peace and blessings be upon him) said: burying it. So it is not permissible. Mosques must be protected, cleaned, purified, and made fragrant, because they are the houses of Allah (Mighty and Majestic) and the gathering place of the angels and the Muslims. They have sanctity and a status that must be cared for. It is not permissible for a Muslim to throw his waste or the handkerchiefs he uses in them, or to spit in them. This is forbidden for him; it is not permissible. Yes.