HG Hardwood Restorer 500ml Treating hardwood garden furniture and restoring its colour? HG hardwood restorer maintains and protects hardwood garden furniture. It deepens the colour and gives a beautiful, natural glow to your garden furniture. Hardwood contains mineral components, which can discolour from the effects of the weather. This can cause hardwood to look grey after a while. With our hardwood restorer greyish garden furniture is a thing of the past!