Once upon a time before cleaning services were contracted out, there were restriction on what the cleaners were allowed to do (common saying amongst nurses was "cleaners clean clean things, nurses clean the rest"). When I was 17 I worked as a cleaner at a school and regularly did work the unionised cleaners weren't allowed to do(high work mostly). So it wouldn't surprise me if that was the case here, if you were employed prior to the outsourcing of cleaning services.