IICRC Fire and Smoke Restoration Technician (FSRT) Practice Exam

Acid cleaners are often referred to as "last resort" options for tough stains on stone or aluminum surfaces due to their strong and aggressive chemical properties. These cleaners can effectively dissolve mineral deposits, rust stains, and heavy grime that other gentler cleaners may not adequately remove.

The use of acid cleaners requires caution, as they can damage certain materials if not used appropriately. On stone surfaces, for instance, some types of natural stone (like marble or limestone) can be etched or discolored by acidic products. Therefore, they are generally reserved for more stubborn stains where other cleaning methods have failed. This is why they are labeled as a last resort.

In contrast, neutral cleaners are milder and safe for a wider variety of surfaces, soap-based cleaners provide a gentle cleaning action suitable for regular maintenance, and non-abrasive cleaners prevent scratching but may not have the potency needed for heavy-duty cleaning. Consequently, when facing particularly challenging stains, an acid cleaner becomes a primary option, albeit with careful consideration of the surface being treated.