Brought to you by PCGamingWiki
Garbage Bag
From Prison Architect Wiki
Garbage bags hold material that can't be reused. For example: after destroying a wall you get some debris; the workmen will put it in a bag, and will place it in the nearest bin or garbage zone.
Garbage bags are also used to dispose of contraband that was confiscated from prisoners. Contraband is found when guards search a prisoner that went through a metal detector that flashed, or when the player gave orders to the guards to search the prisoner.