155 
A solution of 10 parts of strong acetic acid in 100 parts of water is also 
satisfactory. The specimen should be allowed to soak in it until the green 
corrosion has disappeared and given place to the red oxide which may be 
removed by brushing. The after treatment is the same as if the Rochelle 
salts had been used. 
In many cases much of the corroded material may be removed by 
careful flaking and chipping with a fine watchmaker’s chisel or even an 
ordinary pocket knife. The object should be wet, or under water, while 
this work is being done as the dry dust is very injurious to the lungs and 
mucous membrane. Sometimes all the corrosion products may be removed 
in this way. This mechanical treatment should be followed by the Rochelle 
salt bath, drying, and a preservative coating of celluloid. A dilute solution 
of sodium sulphide will give the specimen a darker colour which may be 
preferred to the bright metallic copper. All the above suggestions are 
also applicable to bronze. 
Glass 
Glass specimens in Canadian anthropological collections are generally 
beads. Broken glass may be repaired with the celluloid cement, which is 
colourless. Glass which is disintegrating, a not very uncommon condition, 
should be soaked in water until any infiltrated salts have dissolved, then 
transferred to alcohol, dried, and coated with celluloid. 
Gold 
Gold seldom needs treatment of any kind. If it is dirty, soap and warm 
water are generally effective. If the gold has been engraved, as are some 
bracelets from the west coast, a very soft brush may be employed, but 
care should be taken not to scratch the soft metal. A 10 per cent solution 
of ammonia in water may be used to remove obstinate stains, or a weak 
solution of hydrochloric acid in water to remove incrustations due to 
burial, either in a coffin or in the soil. Thorough washing in several changes 
of water must follow either of these solutions. A final coating with the 
celluloid solution may be added but is not essential. 
Iron 
Specimens that are so badly rusted that little or none of the metallic 
iron is left should be cleaned as far as is practicable, washed to remove all 
contained salts, dried, and soaked in celluloid solution. They may also be 
improved by boiling them in a strong solution of caustic soda or carbonate 
of soda in water. 
When the rusting is only superficial, much of the rust may be removed 
by brushing with a steel-wire brush working under water or with a wet 
specimen. The object is then placed on a layer of granulated zinc in an 
iron or porcelain vessel. More zinc is placed over the object until it is 
completely buried and a 10 per cent solution of caustic soda in water is 
then added, sufficient in quantity to cover the layers of zinc completely. 
It is allowed to simmer gently for several hours. When removed, the 
specimen will be covered with a black deposit. It is again brushed with a 
steel-wire brush and the treatment with zinc and caustic soda repeated if 
necessary. If not, it is dried quickly, preferably in a hot oven, and immedi- 
ately dipped in or painted with the celluloid solution. 
