Brushes, the most underrated tool

Ask a climber to list their most important gear and they will reel off shoes, chalk, maybe a crash pad or a rope. The brush almost never makes the list, which is odd, because of all the cheap bits of kit in a climbing bag, the humble brush probably does the most to help you actually stick the holds. A grease-coated, chalk-clogged hold can be a full grade harder than the same hold brushed clean. People spend a fortune chasing finger strength and ignore the fifty-pence fix sitting in the bottom of their bag.

A climbing brush is a small handheld brush, usually with stiff boar's hair or synthetic bristles, used to scrub chalk, skin grease and rubber off holds. That is it. There is nothing clever about it, and that is precisely why it gets overlooked. But once you understand what it does to friction, you start brushing properly, and your climbing quietly improves.

Why a clean hold grips better

Every time a hand touches a hold, it leaves behind a thin film of skin oils, chalk, and the residue of everyone who climbed before you. Over a session, popular holds build up a polished, greasy glaze. That glaze fills in the tiny surface texture that your fingers and rubber actually grip, and the hold goes from positive to slick.

Brushing scrubs that film away and exposes fresh texture. On small crimps and slopers, where you are relying on friction and the last few millimetres of surface roughness, the difference is dramatic. A sloper you keep sliding off might simply be greasy. Brush it firmly, let the dust settle, and suddenly it holds.

Half the time you are not too weak for the hold, the hold is just too dirty for you. Brush first, blame your fingers second.

This matters most on the worst holds. Big jugs do not care much whether they are clean. The marginal crimps and slopers, the ones at your limit, care enormously, which is exactly why brushing is most useful precisely when you are trying hard.

Choosing a brush

Brushes vary more than you would think for such a simple object. A few things matter.

• Bristle material. Boar's hair is the traditional choice, soft enough not to damage holds but firm enough to clean well. Stiffer synthetic bristles cut through grease faster but can be harsher on rock and on plastic holds.
• Bristle stiffness. Stiffer brushes clean aggressively, softer ones are gentler on the surface. For outdoor rock, lean towards natural bristles to avoid wearing the rock.
• Head size and shape. A bigger head covers slopers fast, a narrow or pointed one gets into pockets and small incut holds.
• Handle and reach. For high holds you cannot reach, a brush on a stick or a telescopic pole saves you stacking pads precariously.

You do not need anything fancy to start. One decent boar's hair brush will do almost everything. As your kit grows, a small pocket brush and a brush on a pole between them cover most situations.

How to brush well

Brushing is not just flicking at a hold for show. Done properly it makes a real difference, done badly it does nothing.

Brush firmly, in the direction across the texture rather than just along it, to lift the grease out of the surface. Then, and this is the bit people skip, blow or let the loosened chalk dust clear before you climb. A freshly brushed hold covered in loose dust is no better than before. Give it a moment, or a puff of breath, so you are pulling on clean, dry rock or plastic.

Brush the feet too, not just the hands. A greasy foothold sends your foot skating off at the worst moment, and clean rubber on clean rock is half of good footwork. This ties into the broader skin and friction picture, which we cover alongside brushing in brushes and skin care for climbers.

The etiquette, indoors and out

Here is where brushing crosses from gear into manners, and the rules differ between the gym and the crag.

Indoors, brushing is generally encouraged and welcomed. Walls often hang brushes near the problems for exactly this reason. The main courtesy is to brush the holds you have used after a hard session, so you leave them clean for the next person rather than glazed with your grease.

Tick marks are the indoor flashpoint. A tick mark is a small dab of chalk to remind you where a hidden hold or foot is. Fine in moderation, but brush them off when you are done, both because it is tidy and because it spoils the puzzle for the next climber who wanted to read the problem themselves.

Outdoors, brushing carries more weight, because you are dealing with irreplaceable rock and a fragile relationship with access. The ethics here are real, and they are part of a bigger conversation we get into in climbing ethics, tick marks, chipping and brushing. The short version:

• Use a soft brush on rock, never a wire brush, which scars and polishes the surface permanently.
• Brush off your tick marks and excess chalk before you leave. A crag plastered in white chalk and arrows looks grim and upsets non-climbers.
• Do not brush holds dry that only exist when wet, and do not over-clean delicate sandstone, which is soft and easily damaged.

The principle is simple. Brush to clean, not to alter, and leave the rock looking as close to untouched as you can.

A small habit that pays off

The best thing about the brush is that building the habit costs you almost nothing and gives back more than its price suggests. Brush the holds before a hard go. Brush the feet. Let the dust clear. Brush down after a session, indoors for the next person, outdoors for the rock and for access.

Chuck a brush in your bag, use it every session, and you will be surprised how often the hold you were sure you were too weak for turns out to have just been dirty. It is the cheapest grade you will ever buy.