Final answer:
The initial step in cleaning non-asbestos acoustical ceiling tiles with light soot involves preconditioning with a vacuum or dry sponge to remove loose particles before applying wet cleaning solutions.
Step-by-step explanation:
The first step in cleaning non-asbestos acoustical ceiling tiles with light soot begins by preconditioning with a vacuum or dry sponge. Preconditioning is essential as it removes the loose soot particles before any wet cleaning solutions are applied, which can otherwise cause the soot to smear. Always use gentle pressure to avoid damaging the acoustical tiles during the cleaning process.