Many houses have pictures darkened with age which only need a little
drastic treatment to make them as fresh and bright as new oleographs.
The surface should first be soaked in a strong solution of hydrochloric
acid and then rubbed with an old nail-brush. Any paint that should
chance to be removed can easily be supplied by a local artist for a few
pence. We heard of a Sir Joshua Reynolds which was treated like this
the other day in its owner's absence, and on his return was mistaken by
him for a Christmas supplement.