The grass that grows near must not be touched by the hand, which seems to impart a very strong scent.

The stick that has been carried in the hand must not be allowed to fall across the run: and be careful that your handkerchief does not drop out of your pocket on or near it.

If a bunch of grass grows very tall and requires parting, part it with the end (not the handle) of your stick.
The same holds good with gins, especially if placed for a rat.

Some persons strew a little freshly plucked grass over the pan and teeth of the trap, thinking to hide it; but it not only smells of the hand, but withers up and turns brown, and acts as a warning to that wary creature.
It is a better plan if any dead leaves are lying near to turn them over and over with the end of a twig till they fall on the trap, that is if they are dry: if wet (unless actually raining at the time), should one chance to be left with the drier under surface uppermost, the rat may pause on the brink.

Now that the remotest chance of leaving a scent was avoided the wire became a deadly instrument.