The bin rule has to be based on the container, not the contents
A cleaner cannot assess whether a document is sensitive, so the rule must attach to the container. General waste and recycling bins with an agreed liner colour are emptied; anything locked, slotted, consoled or labelled for secure destruction is not. That is a rule someone can apply in a corridor at nine at night without needing to read anything, which is precisely why it works.
It also matters that the rule is symmetrical. Just as a cleaner should not empty a secure bin, they should not move general paper into one. Both directions break the chain the destruction contractor relies on and both undermine the tenancy's own record of what was destroyed and when. Stating the rule once, in both directions, closes the issue. It also gives a supervisor a single sentence to repeat to a new team member, which is where most of these rules are actually transmitted.
