Best automotive glass polishes

Start with 3M Glass Polishing Compound — the safest bet for a real correction job: it's made for machine polishing (dual-action or rotary) and is formulated to lift water spots and leave a bright, clear finish. Use it with a foam or rayon glass pad and keep the pad damp.

Who the others suit:

• CARPRO CeriGlass — the best all-rounder for hand or machine work; it handles light scratches and stubborn water spots and is easy to control on a whole windshield.
• Griot's Garage Fine Glass — for mild spotting and general clarity on a car you're not trying to correct; gentle, low-risk, good for upkeep.
• Cerium oxide powders (QENASHAING, HPDDIN) — the traditional route for deeper wiper-track scratches; mix to a slurry and expect to spend time. Results depend heavily on your technique.
• Cheap scratch-remover pastes (Zupieus, WOHSAO, Pnroktd) — fine for a quick try on light haze or small spots, but treat the claims cautiously.

Two things matter more than the brand: work in the shade on cool glass, and don't polish the inside of a windshield with tint or a defroster grid. Deep scratches you can feel with a fingernail usually need a pro.