If you’ve ever been shut down on a climb, hanging off a small crimp with sweaty fingers, desperately trying to find purchase on a hold that feels like polished glass—you know the frustration. You’ve tried harder. You’ve shouted at the rock. Nothing works.
Then a friend walks up, pulls out a small climbing brush from their chalk bag, gives the hold a few quick scrubs, and suddenly the impossible move feels... possible.
The climbing brush is one of the most underrated tools in a climber’s arsenal. It doesn’t make you stronger. It doesn’t improve your technique. But it can be the difference between sending and failing, between flowing and fighting.
In this guide, we’ll explore why brushing holds matters, what types of brushes exist, and how to use them effectively.
Why Brush Holds?
The answer is simple: friction.
Climbing holds—whether on plastic in the gym or rock outdoors—accumulate dirt, oil, sweat, and rubber over time. On plastic, the buildup creates a slick surface that your fingers slide off. On rock, moss, dirt, and chalk residue can turn a textured edge into a slippery mess.
When you brush a hold, you’re not just cleaning it. You’re restoring its natural friction. That extra grip can mean the difference between sticking a move and peeling off.
The Science of Friction
Friction between your skin and the hold depends on two things: the texture of the hold and the condition of your skin. A clean hold maximizes the contact area and allows your skin to grip effectively. A dirty hold creates a barrier—like a thin layer of lubricant—that reduces friction.
For small crimps and slopers especially, friction is everything. On a sloper, you’re not really “holding” it—you’re pressing into it. Without friction, your hand simply slides off. On a micro-crimp, even a thin layer of chalk buildup can change the effective edge depth.
Types of Climbing Brushes
Not all brushes are created equal. Here’s a breakdown of the most common types.
1. The Classic Boar’s Hair Brush
Best for: Gyms, soft rock, general cleaning
The classic climbing brush features stiff boar’s hair bristles. It’s firm enough to remove chalk buildup but soft enough not to damage the hold texture. These brushes are widely available, affordable, and get the job done for most gym climbing.
Pros: Affordable, effective on chalk, gentle on holds
Cons: Less effective on stubborn dirt or moss
2. The Nylon Brush
Best for: Stubborn dirt, outdoor rock
Nylon bristles are stiffer than boar’s hair and more aggressive. They’re excellent for cleaning dirt, moss, and caked-on chalk, especially outdoors. However, they can be abrasive—use them carefully on soft rock like sandstone.
Pros: Aggressive cleaning, durable
Cons: Can damage soft rock or polished gym holds if overused
3. The Wire Brush
Best for: Heavy-duty outdoor cleaning
Wire brushes (usually brass or stainless steel) are the heavy artillery of climbing brushes. They’re used to clean moss, lichen, and deep dirt from rock. Brass is softer than steel and less likely to damage the rock surface, making it the preferred choice for sensitive areas.
Pros: Removes moss and stubborn debris
Cons: Can damage rock if used improperly; not for gym use
4. The Finger Brush
Best for: Small holds, pockets
Finger brushes are small, compact brushes designed to fit into tight spaces. They’re perfect for cleaning pockets, small crimps, and bolt holes. Many climbers carry one alongside a larger brush.
Pros: Reaches tight spaces, lightweight
Cons: Slower for cleaning large surfaces
5. The Chalk Brush Combo
Best for: Gym climbing
Some brushes come with a built-in chalk ball or chalk reservoir. These allow you to brush and chalk in one motion—a convenient option for gym sessions where speed matters.
Pros: Convenient, saves time
Cons: Less specialized than separate tools
When to Brush
In the Gym
- Before your first attempt: Brush holds to remove chalk and rubber from previous climbers
- Between attempts: Sweat and chalk build up quickly; a quick climbing brush before each try keeps friction consistent
- On project climbs: If you’re working a route over multiple sessions, give the holds a thorough clean at the start of each session
Outdoors
- On established routes: Many outdoor climbs see heavy traffic. Brushing removes chalk buildup and restores the hold’s natural texture
- On new routes or first ascents: Cleaning moss, dirt, and loose rock is essential before attempting a new line
- Between seasons: If you return to a project after months away, expect holds to need a deep clean
Brush Etiquette: How to Be a Good Climbing Citizen
Brushing holds isn’t just about your own climbing—it’s about respecting the rock and the community.
In the Gym
- Don’t leave chalk dust everywhere:Brush over the mat or your chalk bag, not directly onto the floor
- Brush before you leave a climb: Leaving holds clean for the next climber is a simple courtesy
- Don’t brush aggressively: You’re cleaning, not sanding. Gentle, firm strokes are enough
Outdoors
- Never use wire brushes on soft rock: Sandstone, limestone, and other soft rock types can be permanently damaged by metal brushes
- Clean holds, not the rock face: Focus on the holds themselves, not scrubbing the surrounding rock unnecessarily
- Pack out old chalk: If you see old chalk balls or debris, consider cleaning them up
- Leave no trace: The goal is to make the climb climbable, not to alter the rock’s natural appearance
How to Brush Effectively
Brushing seems simple—and it is—but a few techniques can make it more effective.
1. Scrub in Circles
Circular motions lift chalk and dirt more effectively than back-and-forth scrubbing. The bristles work into the texture of the hold from multiple angles.
2. Brush Both Directions
For textured holds, brush in different directions to work debris out of the grain.
3. Use a Two-Brush System
Many climbers carry two brushes: a larger one for edges and slopers, and a smaller finger brush for pockets and crimps.
4. Don’t Over-Brush
Once the hold is clean, stop. Excessive brushing can wear down textures over time, especially on soft rock or older gym holds.
5. Brush Your Shoes Too
Rubber buildup on footholds is a common issue. A quick brush of your shoe soles before a hard move can improve foot friction significantly.
Choosing Your First Brush
If you’re buying your first climbing brush, here’s a simple recommendation:
For gym climbers: A classic boar’s hair brush with a comfortable handle. Add a finger brush for pocket-heavy routes.
For outdoor climbers: A boar’s hair brush for general cleaning, plus a brass wire brush for stubborn moss (used sparingly and only on durable rock).
For travel: A compact, foldable brush that fits in your chalk bag or pocket.
Brush Maintenance
A good climbing brush can last for years with basic care.
- Clean your brush: After outdoor sessions, rinse dirt and grit from the bristles
- Store it properly: Don’t leave it in a damp chalk bag; let it dry between sessions
- Replace when worn: When bristles become frayed or bent, it’s time for a new one
The Bigger Picture
The climbing brush is a small tool, but it represents something larger: respect for the climb and the community. When you brush a hold, you’re not just helping yourself—you’re preserving the climb for the next person. You’re acknowledging that climbing is a shared experience, and that small acts of care make the sport better for everyone.
So next time you step up to a climb, take a moment. Look at the holds. If they need a clean, pull out your brush. Those few seconds of effort might be the difference between slipping off the crux and sending your project.
And when you do send—don’t forget to brush the holds on your way down. Someone else will thank you.
Whether you’re climbing in a gym or on real rock, brushing holds is a simple practice that improves safety, performance, and the experience of everyone who follows. Keep your brush close, use it often, and climb with care.