What is climbing chalk?
Climbing chalk is a form of purified soft fine grained limestone that originally began life as fossilized sea shells. It has been used by climbers to absorb sweat and increase grip since the 1950s. It is naturally white being calcium carbonate in the form of the mineral calcite. It is considered non toxic and slightly alkaline.
Why clean chalk off cliffs?
The visual impact from the build up of climbers’ chalk on overhung cliffs is hard to deny. When rainfall does not naturally wash away chalk it can become obvious to land managers and members of the general public. Chalk “graffiti” has been mentioned in numerous access related issues at Australian crags in recent years. Some high traffic climbing areas that are overhung will require regular cleaning for the sake of continued climbing access.
Packed on chalk is also detrimental to climbing performance. Most climbers know that a quick scrub with a toothbrush of a key crux hold can be the difference between sending and failing. The same performance gains can be had for the entire climb if the thick build up of chalk is removed regularly.
Unfortunately scrubbing with a brush does little to remove the really caked on chalk… for that we need water.
Scrub, squirt and collect
Chalk should never be considered a permanent stain on the rock as it really isn’t hard to remove. Chalk is not like paint, glue or grease – it dissolves readily in water (rain is the simple reason why vertical and slab routes never get built up chalk on them). Below we describe the quickest and simplest method to remove bulk climbers chalk from natural rock. This technique has been used successfully on the sandstone cliffs of the Blue Mountains, Nowra and the Grampians. If you are interested in doing a crag chalk cleanup please contact the ACANSW for assistance.
Warning – always seek advice from land managers before doing chalk cleanups on areas that may contain Aboriginal art (you shouldn’t be climbing near art anyway).
Tools of the trade
To clean climbing chalk from rock you will need two water squirters, numerous towels (one hand towel per square metre of rock that needs cleaning) and a soft bristled brush (plastic or natural fiber – no steel). You will also need a large quantity of water – 10 litres per climb is a good guide. A 20 litre drum from BCF works well to transport water in a backpack. Even better – source the water from a nearby creek. You will also want a waterproof bag to store the used the towels and a small bucket to rinse them out into. Do not underestimate just how many towels you need! You will get dirty and wet cleaning chalk – wear appropriate clothes. A ground based assistant (if working on ropes) is essential to help refill water bottles and rinse towels.
This is the least important part of the process and can be skipped. Give the worst chalked up offenders a brisk but brief scrub with a natural or plastic fiber brush to dislodge the big stuff. Never use wire brushes on rock as it damages the rock itself. 5 seconds is about all you need to do per hold – the next step involving water works so much better. When you brush chalk it just turns the chalk particles airborne for a brief moment before they resettle on the rock somewhere else.
Use a hand held water squirter (available at hardware stores and some supermarkets) to squirt 100% water directly on the chalked hold. High pressure mode is key – the force of the water dislodges the built up chalk in deep crevices and cleans the rock quickly. Most people are very surprised just how easily chalk washes off using such a simple tool. Hold the squirter only a few centimeters from the hold you want to clean – don’t indiscriminately spray the entire wall as this just wastes valuable water and can easily create a huge mess (more on that below).
At the same time as you squirt the rock with water you must also hold a towel directly under the hold you are washing. One hand uses the squirter – the other holds the towel. The aim is to mop up any water before it runs down the rock. When rock is wet it just looks like plain water – but this water is actually filled with tiny dissolved particles of chalk. If you let it run down the cliff and dry out it will leave long white streaks of chalk that can look worse than the original problem. This is not an optional step – you must soak up all surface water residue with a towel as this is how the chalk is removed from the rock. You will need plenty of towels. On the ground you will want a bucket of clean water to rinse out the chalk from the used towels. Twist the towels to dry them out (over the bucket – not the bush) and recycle. Never allow chalk infused water to fall onto the ground or plants. Take the chalk infused water back out with you – never dump it on the ground or in creeks.
Vinegar – the secret weapon
Some chalk can be so ingrained that it can feel impossible to remove. White vinegar ($1 at the supermarket) is a mild acid that helps to break down chalk and can be used sparingly in a 2nd spray bottle. This acid is so weak you can drink it – you use it to pickle vegetables. Dilute it one part vinegar to two parts water. Use the same squirt and collect method described above but also vigorously scrub the vinegar into the problem hold with a brush. Rinse with the plain water squirter to remove the vinegar liquid (collect with towel). As vinegar is an acid it is very important not to get this liquid onto your ropes and harness. It is unlikely to cause damage if lightly sprayed – but if you spill it onto your gear get the hell off the rope and throw it in the bin! Dynema slings are not affected by the acid in vinegar.
Vinegar should never be used on limestone rock as it has the potential to dissolve the rock itself (chalk is limestone after all). Some sandstones can also contain carbonate (the cement that binds grains of sand together) that may be affected by acids – but rinsing off as described above should ensure no long term damage. A squirt is about 2ml of liquid – so this isn’t a big amount. We have kept chunks of Bluies rock in a jar of full strength vinegar for over a year and they are still intact with no dissolving of the carbonate between the grains. If this all makes you nervous – stick to water.
Let it dry out
The true result of the chalk clean-up won’t be visible until the rock totally dries. What may look clean when wet may actually still be partially chalked. The process described in this tutorial is not perfect – but it will reduce 95% of visible chalk.
Using water to clean holds will obviously leave the holds wet and unclimbable in the short term. We suggest if you plan to clean chalk off holds using water that you notify local climbers in advance that the section of cliff will be off limits for a day (via Facebook groups etc). A day off is a small price to pay for a squeaky clean crag.
Video demonstration of chalk cleaning techniques in the Blue Mtns
Alternatives to white chalk?
Once your cliff or boulder is free of white chalk it is now worth trying alternatives such as this Aussie made coloured chalk and synthetic drying agents like the Metolius Eco Ball. As you can see in the example to the left any coloured chalk is better than white chalk – give it a go! Of course the best thing to do is not use chalk at all by leaving the bag on the ground. On easy warmup routes this is a no brainer. A simple chalkball will greatly reduce the amount of loose chalk that ends up on the cliff. Lastly, get into the habit of brushing holds when you lower-off a route or finish a bouldering session. A $5 toothbrush will do the job.