Collection happens on-board!! These are bottles, Newspaper, Amul Carton & Ice Cream Wraps...The scene will be obviously this way when cleaning as you can't collect Water Bottles on-board which rests neatly in holer!!
Its akin the way Bedrolls get managed at destination...or situation in Rajdhani's where PC stuffs and bedrolls are dumped at vestibule at night....more like how staff manages & usually they need to be quick (pull and throw bottles at aisle and then broom..or pack bundles of Bedroll which has to be thrown in washer/dryer!!