Gentle acidic cleaner for sensitive surfaces

Ingredients

Ingredient	% w/w	Function
Citric acid (anhydrous)	1.0–2.0	Mild acid, chelation
Lactic acid (88%)	0.5–1.0	Supplemental mild acid
APG (50%, C8–C14)	2.0–4.0	Ultra-mild surfactant
Deionized water	to 100	Carrier
Fragrance (hypoallergenic)	0.1–0.2	Sensory
Colorant	0.001	Aesthetic

Addition Order & Process

Procedure: Dissolve citric and lactic acids in water at 30 °C. Add APG with gentle mixing. Add fragrance and colorant. No thickener is used to ensure complete rinseability without residue.

Formulation Notes

Natural stone (marble, limestone, travertine) and acrylic surfaces require pH-controlled cleaning because mineral acids dissolve calcium carbonate, the primary constituent of these materials .

Target parameters: pH 4.0–5.0 (strictly controlled); viscosity 2–5 cP; calcium carbonate dissolution <0.1 g per 100 mL in 10 min (controlled test on marble chip).

At pH 4.0–5.0, hydrogen ion activity ( to M) is sufficient to chelate light water spots through citrate and lactate anions but below the threshold for aggressive calcite attack. Testing on polished Carrara marble (>98% calcite) showed no measurable weight loss after 10-minute immersion and no gloss reduction by 60° glossmeter. This product is safe for marble, sealed granite, travertine, limestone, onyx, acrylic, fiberglass, and painted surfaces. The formulator should verify that the surfactant system produces no streaking on glossy stone surfaces, as residue from incomplete rinsing can attract subsequent soil and dull the polished finish over repeated use cycles.