Collinite 435 Streak Fixer Black Streak Remover

If you've ever owned a caravan, motorhome or boat, you'll probably be familiar with the black streaks that gradually appear beneath windows, seals, roof edges and fittings. They can be surprisingly stubborn, often remaining visible even after a thorough wash.

These marks generally develop as rainwater carries accumulated dirt and contamination down the exterior surface. Over time, the deposits can leave dark, unsightly trails across otherwise clean bodywork, particularly on white fibreglass and gelcoat finishes.

Collinite No. 435 Streak Fixer has been developed specifically to deal with this problem. Rather than relying on aggressive scrubbing, it uses a spray-on cleaning formulation to help lift black streaks, light surface stains and fresh water spot deposits from compatible exterior surfaces.

What makes it particularly useful is that it doesn't simply stop at cleaning. Streak Fixer also contains a fast-bonding polymer ingredient that leaves a protective finish behind as you work. That makes it an appealing choice for keeping a previously detailed vehicle looking its best between more thorough cleaning sessions.

We particularly like this approach for caravans and motorhomes. These vehicles often have large exterior panels, but the unsightly marks tend to appear in relatively localised areas. Being able to deal with individual streaks quickly, without having to wash and re-protect the entire vehicle, is a genuine convenience.

Collinite also confirms that No. 435 is designed to preserve existing applications of its marine waxes, including No. 845 Insulator Wax. That's an important distinction from more aggressive cleaners or polishing compounds, which may remove existing protection while correcting surface defects.

The product is also versatile. Although black streak removal is its main purpose, it can tackle mild surface staining, light scum and fresh mineral water spots. It is intended for compatible fibreglass, gelcoat, painted and metal surfaces, making it useful across a variety of exterior applications.

However, there are limits to what it can achieve. Streak Fixer isn't designed to remove heavy oxidation or restore badly faded gelcoat. Those problems require more intensive cleaning, compounding or polishing. Likewise, heavily soiled surfaces should be washed properly before attempting localised stain removal.

Application is refreshingly simple. Spray a small area, work the cleaner over the affected surface with a microfibre towel, then immediately remove the residue using a second, dry towel. Stubborn deposits may need a repeat application, but there's no complicated curing process or specialist equipment involved.

For customers already using Collinite 845 Insulator Wax, Streak Fixer is a particularly sensible addition to the maintenance kit. It allows you to target the marks that develop between washes while helping preserve the underlying protective finish.

For us, Collinite 435 is one of those specialist products that makes a frustrating job much easier. It isn't a replacement for proper washing or paint correction, but for black streaks and localised staining on boats, caravans and motorhomes, it's an extremely useful product to have close at hand.