Cross-contamination is a sequencing problem, not an effort problem
A workshop floor holds oil film, tyre rubber, coolant traces and fine metal particles. Once that mixture is on a mop head or a vacuum sole plate it travels, and it will show first on the lightest surface in the building, usually the lounge carpet or the tiled entry. No amount of scrubbing in the front area fixes a problem that is being reintroduced by the equipment used to clean it.
The correction is procedural. Separate colour-coded equipment is allocated to workshop and front-of-house zones, stored apart, and never rotated between them. Work runs front to back within a shift so soil moves in one direction only. This costs nothing extra to specify but has to be written into the plan, because a relief cleaner will otherwise apply whatever sequence seems efficient.
