Prestone AS242 Windshield De-Icer

Prestone AS242 is a methanol-based aerosol deicer that clears frost and ice fast — reviews consistently describe rapid clearing within seconds of application. The formula uses methanol at 45–70% concentration rather than isopropyl alcohol, making it more effective at extreme cold but significantly more toxic. No documented paint, seal, or trim damage from normal windshield use. The 11 oz aerosol can includes a built-in polycarbonate ice scraper cap; reviews call the scraper mediocre compared to a dedicated tool, but the spray itself earns strong loyalty from repeat buyers who stock up before each winter.

Best for cold-climate drivers who park outside and need rapid ice clearing without extended scraping sessions — the methanol formula delivers genuine cold-weather performance. Skip it if you have children or pets with access to your vehicle supplies — methanol is acutely poisonous in small quantities and cannot be made nonpoisonous. Households concerned about handling toxicity should consider an IPA-based deicer, which scores significantly higher on health while still clearing ice effectively at moderate winter temperatures.

The SDS carries DANGER from health H-codes: H301 (toxic if swallowed), H311 (toxic in contact with skin), H331 (toxic if inhaled), and H370 (specific organ toxicity — optic nerve and CNS damage). This is genuine acute toxicity, not a physical flammability warning. Proposition 65 applies for reproductive harm (methanol + ethylene glycol). Eye protection, chemical-resistant gloves, and respiratory precaution are all justified by the SDS hazard classification for any scenario where aerosol mist contacts the face during application. Environmental footprint: high VOC from methanol content; methanol is readily biodegradable per SDS §12; neutral road-runoff pathway with no aquatic toxicity concern.