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How To Use A Grout Pen – From Grubby To Spectacular!

This post concerns grubby grout and grout pens. It is rather long, so I’ve added jump links to take you to the important sections in a jiffy. Just click through to the section of interest, alternatively read everything.

Grout gets grubby over time. There’s no getting away from it. Here’s this all too familiar problem laid out eloquently by a disgruntled Mumsnet user. The frustration just drips from her forum post.

I have spent hours over the last few days scrubbing the grubby wall tile grout in the kitchen… Had a look on the internet and made a bicarb and bleach paste, put on with a toothbrush and scrubbed off with a wire scourer. The grout is now kind of light grubby grey rather than black, and the embossed tiles themselves look much better, but I want the grout WHITE dammit…

Ring any bells?

For many people the answer to grubby grout involves a lot of scrubbing, probably bleaching and usually frustration. So why don’t people just reach for the nearest grout pen?

The problem is not all grout pens are made equal, and that is the reason why this particular Mum went for a different solution.

the reviews for the grout pens say they take ages and are really smelly (am preg) and the nibs run out quickly. Have loads of tiles to do so might need 3 x pens, so £30.
I have already spent HOURS cleaning this kitchen. I want a quick grout fix, tell me the pens work!

The Mumsnet contributors suggest other solutions to grout pens because of bad reviews. Rainbow Chalk pens have been around for a long time and tend to have great reviews because they make grubby grout look fantastic. However, it’s clear that some people struggle, so the next section illustrates how to get the most from your Rainbow grout pen. Don’t worry it’s very easy!


1. The Rainbow Grout Pen restores grout beautifully – here’s how!

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These grout pens are extremely easy to use, people go wrong for one main reason. So follow these straightforward instructions and get spectacular grout every time

  • 1. Pump the pen to activate the ink
  • 2. Keep going, you may need to pump as many as ten to twenty times
  • 3. Test for ink flow
  • 4. Stop pumping when the ink flows from the tip

As stated it can take a little while for the ink to prime, so don’t give up, keep pumping. Then use the pen on the miscreant grubby grout, reviving it beautifully. The ink flows until you stop using it. Start again by pumping to re-prime the pen. Simple.

Hold the pen at an angle to keep the ink flowing and apply a smooth, steady pressure. Keep a dry and damp cloth handy to wipe up any surplus ink. Easy…

2. Other methods of reviving grubby grout just don’t compare

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There are other approaches but none come close to the convenience and ease of using a grout pen. Here’s a quick comparison to a few alternatives to illustrate why…


One way to ensure your bathroom or kitchen grout is restored to its former glory is to go the whole hog. This is a bit drastic unless your grout is in a desperate state. You will require a regrouting tool of some description to scrape or cut out some of the offending grout and apply fresh. This is a worse option than a grouting pen because

  • The pen is easier to use
  • It’s quicker and cheaper – you will only need one application

BONUS – In addition, the pen’s ink has anti-fungal and anti-bacterial properties which help prevent the re-emergence of mould and eventually grubby grout. So once applied the refreshed grout will stay refreshed longer! 1-0 to Rainbow!

Mould/Mildew Remover

This option requires you to apply the product and waiting for the magic to happen. It does work well, however some reviewers suggest it is not always successful at removing offending stains from the grout itself.

In addition it is pretty toxic, and there are specific safety warnings

  • Irritating to eyes
  • Irritating to respiratory system
  • Do not breathe spray
  • In case of contact with eyes, rinse immediately with plenty of water and seek medical advice
  • Use only in well-ventilated areas
  • If swallowed, seek medical advice immediately and show this container or label
  • Keep out of the reach of children
  • Wear suitable gloves

Rainbow grout pens are completely safe and non-toxic because the ink has a water-based formula. Our Mumsnet correspondent would not have to worry about potential harm to her unborn child. 2-0!

Aerosol Grout Sealer

One of the mumsnet commenters suggested an aerosol grout sealer be used after scrubbing the grout back to its white state. Obviously, this approach is reliant on getting the grout back to that state. Assuming that is achieved, the grout sealer could be used to help keep it that way.

The trouble with any aerosol is the flammable gasses which may cause a risk and may be of concern to a pregnant mumsnet user. As stated, the Rainbow pen is water based and completely non-toxic, with no fumes or gasses! 3-0 and game over!

  • new white grout pen 5mm

    Grout Pens 5mm Nib

    £3.50 incl. VAT

3. Great grout pens are the answer but why choose Rainbow?

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As mentioned previously, not all grout pens are equal and a quick Google search will reveal a number of negative reviews. Rainbow pens are the best option for the following reasons.

Our nibs outlast the ink!

Rainbow’s nibs do not wear out before the ink is used up because the nib is reversible. Essentially, you can use it twice! If this Amazon user had read this article it might have helped them out!

Besides, our pens cover about 60m of grout and the nibs are built to last longer than that. There can be times when the grout finish is particularly rough and could, in theory, damage a nib making it wear out sooner than we’d like, hence the reversible nib feature.

Not all grout pens have this feature, which makes them inferior, because worn out nibs really shouldn’t be a problem.

Touching up tired grout

Grout will not deteriorate at the same rate. Keeping a grout pen handy means you can touch up grubby spots as they appear. There’s no need to suffer grubby grout at all, just think of your grout pen as a grout cleaner! Store the pen nib down and prime it before use. Easy!

Coloured Grout

Rainbow grout pens come in a selection of colours. This allows you to refresh different coloured grout and provides you with a great way to not only spruce up your kitchen or bathroom but also completely alter the look in just a few strokes of a pen!

Bored of white grout? Select from six colours and transform the look of your bathroom or kitchen, easily and cheaply!

Imagine the scenario. Grey grout seemed like a good idea in the tile shop but you hate how it makes your bathroom look. The tiles are brilliant, the furniture and appliances are fabulous but you just can’t get used to the grey grout. Rainbow have the answer, take a grout pen to it! Apply one of six colours and your grout is re-coloured in a jiffy.

Thick and Thin Nibs

Rainbow grout pens come in two nib sizes. The 7ml pen has a narrow nib for a grout joint of about 5mm. The 20ml pen is much thicker and ideal for a wider grout joint. It all depends on the tiles and grout joints. Have a look and choose the pen that works for you.

4. Reviews – what they say on Amazon

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There are a lot of reviews for Rainbow grout pens on Amazon, for both the narrow and wide nib pens. The vast majority of these reviews are very positive. The narrow nib page has 121 reviews, of which 93 score four or five stars. That’s a very high approval rate, here’s one of these

Like New!

Excellent product!
I really wasn’t expecting such a good result. I have been scrubbing & steaming the grout on & off for over a year, with no real difference! I bought this product as a last resort to prevent me having to re-grout & WOW was I pleasantly surprised. It really does work & the grout looks like it has been newly applied (bright white).

And another recent  review

A very good product will buy again

Did exactly what it was designed for. Blended well with old grout so I did not have to do the whole wall, just the damaged bits. A very good product will buy again.

People love the results from our grout pens and so will you. Rainbow pens are the best! So what’s stopping you? Click here to choose your grout pen or take a look at our product boxes below!


  • new white grout pen 5mm

    Grout Pens 5mm Nib

    £3.50 incl. VAT
  • Large white grout pen

    Grout Pen 15mm Nib

    £5.50 incl. VAT

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