The Gyannis note down where they finish , so that the next gyanni or when they return to carry on with the patth can start of from the correct position. Therefore they have to write down Angs from Sri Guru Granth Sahib Ji on a note pad, after the sehaj patth is finished this notepad or paper from the note pad ends up in the bin.
Is the Bin a place for Gurbani?
is this holdong Gurbani in high regards?
The correct and respectful thing to do would be cremate the paper.