Musannaf Ibn Abi Shaybah

Hazrat Ibn Tawoos narrates that when a large number of letters would accumulate with Hazrat Tawoos, he would order them to be burnt and they would be burnt.

Hazrat Nu'man bin Qais narrates that Hazrat Ubaidah made a will that his letters should be erased.

Hazrat Abdullah bin Muslim bin Yasar narrates that when a letter would come to Hazrat Muslim bin Yasar, he would erase the mention of Allah from it and then throw it away.

Hazrat Aswad bin Hilal narrates that a scroll containing some hadiths was brought to Hazrat Abdullah bin Masood (may Allah be pleased with him). He called for water, first erased it, then washed it, and then ordered it to be burned, so it was burned.