Cleaning Bronze
Keep bronze pieces as clean as possible. Accumulations
of dust and dirt can eat into the metal surface. Dust
regularly using a soft cloth. Do not rub too vigorously,
especially on any protruding parts.
If a bronze piece has been neglected for a long time
and is covered with grime, thoroughly clean it with a soft
brush. Remove all dust from crevices and notches and then
lightly rub the entire surface with a soft flannel cloth.
For a more thorough cleaning, carefully wash with a
solution of 1 tablespoon of salt and 3 1/2 quarts of
water. Rinse well. Polish with copper polish followed by
glass wax.
If you want a high polish, dip a cloth into liquid
wax and apply to the piece. When dry, buff lightly to a
high gloss. This wax treatment also may be given to bronze
pieces that are kept outdoors. Weathered bronze usually
darkens; however, this is natural and does not harm the
piece.
"Bronze disease" is one of the most serious hazards
of bronze. This disease, caused when chlorides and oxygen
combine in a damp environment, also attacks brass and
pewter. The disease takes the form of a sudden outbreak
of small patches of corrosion and is distinguished by
rough, light green spots. "Bronze disease" usually can be
stopped by washing the piece in repeated changes of
boiling hot, distilled water. You may have to soak the
object for a week or more in distilled water. If this
treatment does not work, consult a museum expert about
using a strong solution of sodium sesquicarbonate or have
your piece treated by a professional.