Keep everything dry.

Keep the mercury hot.

Follow these instructions carefully, and you must succeed.
HINTS AND CAUTIONS.
First of all, cleanliness should be observed.

When there is dust or dirt about your room, particularly about the work-bench, failures will be frequent; for the smallest particles of rotten-stone, when allowed to come in contact with the buffs, will produce scratches on the surface of the plate, which very much injures the operation, and often causes failures.
Dust flying about the room is injurious, if allowed to fall on the plate, either before or after it has been coated, as it causes black spots which cannot be removed.
The polished plate should not be allowed to come in contact with a strong current of air, for it tends to oxidize the surface.

Breathing on the surface should also be avoided, for the same reason.
The plate should, in all cases, be buffed immediately before using, and not allowed to stand any length of time.