How do I remove marks from the soundboard?

While the guzheng is being played the soundboard faces upward, so airborne dust settles on it readily, and dust between the bridges is especially hard to reach. Do not wipe the soundboard with a damp cloth — a large area of absorbed moisture will make the instrument sound dull. A guzheng cleaning brush removes the dust easily. Avoid polishing the soundboard with wax-based products as well: it makes the bridges prone to sliding and jumping.