Diminish if the wood is used outdoors, as it is affected by ultraviolet light and by the weather; a pleasing silvery grey patina develops. The wood turns grey slower if it is treated with pigmented oils and varnishes; if it is treated regularly (once or twice a year), the colour desired can be preserved.

Real dirt, patches of rust or water stains can easily be removed with a wire brush or with sandpaper; minor soiling with a scrubbing brush. We recommend treating terrace decking regularly if it has been treated with oil.

If the need arises, a special deep-cleansing agent (based on fruit acids) is available for weathered wood that has turned grey. The agent makes it easier to remove varnished surfaces that have been destroyed, removes algae and lichen etc., and lightens the hue of untreated wood while deep-cleansing it.