CARING FOR YOUR CANE FURNITURE
Some furniture (particularly furniture living on the coast and exposed to heavy mists) can form a residue over time. Iron oxide stains in wood are usually dark spots caused by prolonged exposure to water and / or metal. The iron oxide reacts with the tannins in the wood and stains it black.
The best ways to restore this would be to use Oxalic Acid. You can buy it from any hardware store – then simply just dissolve it in water and brush the affected area. Put it out in the sun to dry and revarnish it, if you had a varnished product.