Glass protection performs best on a clean, residue-free surface. Ordinary glass cleaner removes loose dirt, but bonded oil film, mineral residue, and old protection may require a dedicated preparation step.
A practical sequence
- Wash and cool the glass.
- Use the appropriate oil-film remover or glass-polishing product for the contamination.
- Work evenly and do not allow the product to dry.
- Rinse or wipe away residue completely.
- Inspect for uniform wetting before applying protection.
Use only products intended for automotive glass and protect nearby trim. Watch the original Andrew Rose demonstration on YouTube.