Cleaning Science, Chemicals, and Equipment
Chemistry drives results
The core concept is the soil-chemistry-match: the right chemical for the soil type, at the right dilution, with the right dwell time and agitation. Candidates must know the major categories: alkaline detergents for organic soils, acidic descalers for mineral deposits, neutral cleaners for routine surfaces, and disinfectants that require a clean surface and full contact time to work. Understand that disinfectants do not clean, and that soil left on a surface inactivates the active ingredient.
Dilution and safety traps
The most frequent trap is dilution error. Over-concentrating wastes chemical, leaves residue, and can damage finishes; under-diluting fails to clean and breeds complacency. Know how to use a proportioner and verify it with a titration check. Another trap is mixing chlorine bleach with an acid or ammonia cleaner, which releases toxic gas. Watch for questions about chemical compatibility with surfaces, such as acid on marble or abrasive pads on stainless steel.
Equipment
Understand the difference between wet and dry vacuuming, the purpose of HEPA filtration, and why floor finish requires stripping before recoating rather than layering indefinitely. Know that microfiber reduces chemical use and cross-contamination when color-coded.
Rule of thumb
Follow the manufacturer's dwell time exactly; a disinfectant wiped off after ten seconds has not disinfected anything. Verify dilution at the start of each shift, not once a month.