104 
NSTRUCTIONS FOR COLLECTING 
should remember that Exotic fresh water and 
land shells are in very great request ; and 
that no shells should be rejected on account 
of apparent similarity. 
With respect to cleaning shells, all that is 
necessary is to put them for a short time into 
a solution of potash and soft soap, half a 
pound of each to half a gallon of water, and 
then to rinse them in clean water and wipe 
them dry. Rough shells will require a brush, 
but those with spines must be carefully handled 
to preserve them whole. 
The operation of polishing shells is one of 
great nicety, and requires considerable prac- 
tice. The conchologist seldom resorts to it, as 
the characters of the species are thereby in 
a great degree destroyed. But many of those 
with rough coats, as the Ear Shells, {Haliotes, 
&c.) are so very splendid, that, if specimens 
abound a few might be polished, their extreme 
beauty (otherwise not discovered) will amply 
repay the labour bestowed on them. With 
others, however, it is necessary to remove 
extraneous substances. The ingredient used for 
these purposes is nitric acid of different degrees 
of strength applied with a horse-hair pencil. 
When the acid used has evaporated, muriatic 
acid and sand must be rubbed on until the 
