Black Streak Removal On Caravans/Motorhomes

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If you are a caravaning beginner, you may not be aware that cleaning black streaks off a caravan can be a bit of a thankless task. I know several of our guests who carry out black streak removal on their caravan at least once a year, sometimes more. Now, arguably cleaning a caravan roof is more of an arduous task. However, with a caravan roof, people won’t see it, so you won’t get judged on the results. With this post, I wanted to address the topic of black streaks on caravans and motorhomes from a couple of angles. First, what actually causes the black streaks on caravans and motorhomes? How do you remove black streaks, and finally, are black streaks preventable?

Black Streak Removal on Caravans and Motorhomes
Nobody likes to see black streaks on their caravan or motorhome. So in this post, I’ll discuss what black streaks are and how to remove them (safely).

Now, how hard it is to remove the black streaks on your caravan will depend on a couple of different factors.

For instance, if you have purchased a second-hand caravan or used motorhome that has been left idle and not cleaned for a prolonged period of time, you probably have your work cut out for you.

On the other hand, if your caravan or motorhome is relatively new, while black streaks may still appear, they are generally easier to remove.

As always with my posts, hopefully, you have the time to read this post in full. However, if not, please use the Table of Content below to jump to particular sections.

Disclaimer: Hey! By the way… any links on this page that lead to products on Amazon or Caravan Guard are affiliate links, and I earn a commission if you make a purchase, with no additional cost to you 🙂

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What Are The Black Streaks On Caravans & Motorhomes?

Ok, I could just say, ‘the black streaks are general dirt/algae which often collect around the windows, vents and doors …‘. But that’s a bit too simplistic and not the full story.

You will generally find black streaks under and around doors, windows and vents on a caravan.

In some instances, yes, its due to a build-up of dirt/algae. There are lots of ways to describe the associated dirt, some of it is algae, moss and general ‘biofilm’.

Biofilm is simply a general term to describe a collection of various bacteria and microorganisms. Above the windows and doors of a caravan/motorhome, there are little gutters that channel the rain.

Well, over time and particularly over winter when the caravan is in storage, this biofilm loves to grow and concentrate in these gutters.

When it rains, some of that biofilm is washed out of the gutter and down the side of the caravan. This can be one potential cause of, you guessed it, black streaks.

However, the main cause of black streaks is actually to do with the rubber seals around windows and doors on caravans and motorhomes.

Denaturing Rubber Seals Around Windows & Doors

The main cause of black streaks on caravans and motorhomes is rubber seals. Well, over time, rubber denatures (breaks down), and bits come of it, leading to black streaks.

Its pretty unavoidable, UV damage from the sun and temperature changes denature all rubber-based products.

Hence, why caravan tyres have to be changed every five years even though they often have lots of tread left on them.

Caravan Black Streaks
A typical example of a large black rubber seal around this door window which Fenwicks used to demonstrate their black streak remover: Image –

So in many cases, the main cause of black streaks will be a denaturing rubber seal. However, once those denatured rubber particles start to run down the caravan, they also attract other dirt.

Therefore, generally, black streaks will be a combination of denatured rubber and dirt.

How To Remove Black Streaks On Caravans & Motorhomes

So now I’ve covered what the black streaks on caravans and motorhomes are, let’s discuss how to remove them. The first thing I want to state is please don’t try and use T-Cut to remove black streaks.

I’ve previously referred to using T-Cut in my post on how not to clean a caravan.

If you are not sure what T-Cut is or why you shouldn’t really use it to clean your caravan or motorhome, please read that post.

Just quickly, its essentially an abrasive polishing agent. And while it probably would remove the black streaks on your caravan or motorhome paintwork, its probably going to take some of your paint along with it.

Where possible, I like to use a video or two in my posts. In the video below, Dan was reviewing Mellerud cleaning products.

As part of that review, he also used their black streak remover and discusses the cleaning process.

In the video, Dan decides to attack the black streaks straight away before a general clean.

Personally, I would approach stubborn black streaks on a caravan or motorhome after the surface has generally been cleaned for two reasons.

First, your standard wash-down with diluted soap may take off most of the streaks. Secondly, as black streak remover products are a concentrate the cost per area for cleaning is higher.

Hence, you don’t want to have to use black streak remover unless you really have to.

I would agree with Dan that using microfiber cloths, mitts and brushes along with a suitable black streak remover is the way to go.

There are a couple of products on the market, but which should you choose? I’ve heard from our guest’s supporters, and detractors of Fenwicks Streak Remover.

But that’s going to be the case for most products. Some people rate them, others don’t. It will often depend on how long those black streaks have been left there etc.

All I can really say is to read the reviews and make up your own mind. For reference though, I’ll provide some examples of popular black streak remover products below.

Black Streak Remover Products

So obviously, the first product I should reference is Mellerud, used by Dan in the video above. I’ve personally not used this black streak remover before, and none of my guests has previously referenced it.

Dan seems to be getting along well with it in the video above though, so it may be worth a try.

When Dan uses the brush to clean around the pull handle, the Mellerud cleaner does foam up well, which can often help to lift dirt off surfaces.

It comes in a 0.5 litre spray bottle, and it is pricey compared to the alternatives below. Is that additional cost justified in black streak removal performance? I’m not sure about that one until I’ve tried it.

It appears that Mellerud actually refers to their black streak remover as ‘rain strip remover’. Its also described as a general degreaser to remove stubborn stains from road oil etc: Image –

Fenwicks Black Streak Remover

I’m aware that several of our guests use Fenwick’s black streak remover, and they are generally happy with the results. Particularly stubborn black streaks may require repeat applications.

It comes in a 1L bottle and is significantly cheaper than the alternative Mellerud product. Remember, this is a concentrated cleaner, so you don’t want to dilute it down.

Spray it onto the black streaks and leave it to work for a couple of minutes before wiping it off, hopefully along with the black streaks.

Fenwicks product generally does a good job at removing black streaks. However, if the caravan has not been cleaned in a long time it may struggle. Even with repeat applications: Image –

Muc-Off Bike Cleaner?

Now, I’ve never used Muc-Off before, and it is technically a bike cleaner, but one of our guests swears by the stuff, particularly for removing black streaks on their caravan.

Is it safe to use on caravan or motorhome bodywork? I’m not sure.

With it being ‘100% biodegradable’, I can’t imagine it contains ingredients that would damage the paintwork, but it doesn’t technically state its safe for use on caravans and motorhomes.

While technically a bike cleaner I’ve heard positive reports of Muc-Offs ability to remove black streaks. But is it a safe product to use on your caravan or motorhome? I’m not sure: Image –

Camco Pro-Strength Black Streak Remover

The last product I thought worth mentioning is from Camco. Camco Manufacturing (their full name) was not a company I was previously familiar with.

It appears to be a US-based company selling various products for the leisure vehicle and RV market. It appears to have reasonable reviews as a black streak remover, so it may be worth a try.

The thing that caught my eye, and in classic American style, is you don’t buy this stuff by the half-litre, or even a full litre, it comes by the gallon!

So if you have some serious black streak removal to be getting on with, this gallon spray bottle may be for you.

If your caravan or motorhome (RV) is covered in black streaks this huge gallon of remover may be worth considering: Image –

Preventing Black Streaks From Returning

Now, unfortunately, I’ve got some bad news. Unless you are constantly cleaning your caravan or motorhome, the black streaks will return.

Likely come springtime, when you get your caravan or motorhome out of storage is when you’ll see them. However, what you can do is try and ‘get ahead of the curve’.

That includes two steps. First, when you wash your caravan, open the windows and doors and wipe down the rubber seals with your chosen black streak remover.

This will remove the denatured rubber particles off the seal’s surface before they start running down your paintwork.

Secondly, after you have cleaned your caravan or motorhome, use additional products. For instance, in my winter storage tips, I discuss applying an overwintering protector.

What this effectively does is makes the surface slippery. With less friction, dirt/rubber particles find it harder to stick to the paintwork.

Now eventually, those dirty black streaks will appear. But come spring, it should be easier to remove them.

When its not winter and you are washing your caravan during spring, summer and autumn, the equivalent surface protection product is… Bobby Dazzler!

We use Bobby Dazzler on my father’s caravan. We find it does help to repel dirt and it also makes it harder for black streaks to form: Image –

Conclusions On Removing Black Streaks From Caravans & Motorhomes

Spending hours toiling away trying to remove black streaks from bodywork could be seen as a right of passage to being a ‘true’ caravanner or motorhome owner.

That may be true, but nobody likes to do it, and its frustrating to spend several hours cleaning your caravan or motorhome to still see black streaks.

Often it will take more than diluted soapy water to shift black streaks, such as one of the products above.

However, don’t be tempted to use something too abrasive such as T-Cut. You’ll probably end up regretting it. To learn more, you may be interested in my round-up post on how to clean a caravan.

Anyway, I hope you found this post on how to (and how not to) remove black streaks useful.

I also hope, at some point in the future, you will consider coming to visit us here at Horton Common to experience our fully serviced hard-standing pitches. 🙂

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