The brass nails on a sadhu board do two jobs. They press evenly into the soles of your feet to stimulate the nerve endings, and they tell you, by the colour of their patina, how often your board is used. New nails are bright. Year-old nails are honey gold. Decade-old nails are a deep, dark bronze.
Most practitioners come to love the dark patina. It is honest. But there are good reasons to polish: you want photographs that show the geometry clearly, you are passing the board to someone new, or the patina has gone uneven and the visual rhythm of the rows is broken. This guide is for those moments.
What patina is and why it matters
Brass is roughly two-thirds copper and one-third zinc. In air, the copper reacts with oxygen, sulphur and skin oils to form a thin protective oxide layer. This is the patina. It protects the metal below from deeper corrosion. Polishing it off is purely cosmetic; the nail underneath is the same brass it always was.
If the patina is even and dark, leave it. If it is patchy, green, or has white salt-like spots, polish.
What you will need
- A jar of brass polish. Brasso, Wenol, Autosol, or any similar metal-polishing cream.
- Cotton swabs. Lots of them. A box of two hundred is not too many.
- A small soft cloth for buffing. An old t-shirt cut into squares works.
- Painters' masking tape, the low-tack kind that does not pull finish off wood.
- A toothpick or wooden coffee stirrer.
What you should not use: steel wool, sandpaper, or any abrasive pad. They will scratch the brass and grind polish into the wood grain around each nail.
The wood protection step
Brass polish stains wood. It contains fine abrasives suspended in an oily solvent, and that solvent carries pigment deep into open wood pores. Once it is in, it is in. Spend ten minutes here:
If your board has tightly spaced nails, mask the wood around small clusters with low-tack tape. You do not need to do the whole board at once. Work in patches of twenty or thirty nails, mask the patch, polish, unmask, move on.
If the nails are widely spaced, a simpler trick: lightly oil the wood around each nail first with the same oil you use for maintenance. The oil saturates the pores so polish cannot soak in. Wipe excess oil off the nail heads before you start.
The polishing motion
- Dab a small amount of polish onto a cotton swab. The swab head should be damp with polish, not dripping.
- Apply to one nail head. Rotate the swab against the brass in small circles for ten seconds.
- The polish will turn black as it lifts oxide. This is normal.
- Flip the swab to the dry end and wipe the nail clean.
- Take a fresh swab and buff the nail until it is bright.
- Move to the next nail.
Yes, this is slow. A full-size sadhu board with several hundred nails takes a focused hour. Put on music. It is meditative work, which is fitting.
If polish gets on the wood
Do not panic. Wipe immediately with a dry cloth. If it has already soaked in slightly, dampen a cloth with mineral spirits and dab gently. Then re-oil that area when you are done. A small dark mark may remain, but it will blend into the patina of normal use within a few months.
The final wipe-down
When all nails are polished, remove any tape. Use a clean cloth dampened with a drop of dish soap in water and wipe the wood surface to remove any residual oil or polish dust. Dry immediately. Then re-oil the wood lightly using the method in our wood oil maintenance guide.
How often
Most owners polish once and never again, because they realise they prefer the look of patinated brass on aged wood. If you do polish regularly, once a year is plenty. More often than that removes a tiny amount of brass each time and over many years will round off the geometry.
A note from the workshop
At our Kostopil workshop, founder Eugene Oliynyk leaves his personal board unpolished. The nails on his daily-practice board have gone almost black at the heads where his arches press. He reads them like rings on a tree. Every owner finds their own answer to this question. The board does not mind either way.
A small ritual
If you are polishing to mark something — handing the board down, starting a new chapter of practice, cleaning before a retreat — make the polishing itself part of the ritual. Sit on the floor, take your time, do one nail at a time. By the end, the board looks new and you have spent an hour with it the way you spend an hour on the soles of your feet during practice. Browse our full collection of handcrafted tools if you are thinking about adding a second board for travel or sharing.
About the author. This piece was written by Eugene Oliynyk, founder of METADESK, together with the workshop team in Kostopil, Ukraine. Eugene has practiced daily on sadhu boards since 2018, including the most advanced 20 mm nail-spacing boards. METADESK has been handcrafting wooden wellness tools since 2016. Reach the team at metadeskukraine@gmail.com.