If there be several duplicate keys to a front door lock, it is advisable to number them in some way, as by filing nicks in the shank or bow, and to note the number of the key assigned to any user. The unpleasantness of being locked out of the house through having forgotten to take out the latch key, or having lost it, will not occur if a duplicate for emergencies is secreted in some easily accessible place outside the house.
Barrel keys – those with hollow sbanks – give trouble if pocket fluff or other dirt accumulates in the barrel. The key will work stiff at first and finally refuse to turn, as it cannot be pushed in far enough. The obstructive matter may have packed so hard that its removal will need the use of a bradawl, twist drill, or red-hot wire.
Where a number of outhouses have to be locked up every night and the keys brought indoors, the keys should be hung on a board provided with just as many hooks as there are keys. A glance at the board will then show if any, or how many, keys are out.
Painting the shanks of big keys yellow or red makes it easier to find a key if it be dropped; while a colour scheme assists in identifying keys.
When valises, hat-boxes, etc., are stored away, their keys should not be left in the locks, lest they should be lost or damaged, but be tied to the handles.
Duplicate keys not in ordinary use – especially those of important locks – should be labelled to indicate to what locks or articles they belong, and-be kept in a safe place. If left lying about or where they can easily be got at, they become a danger.
Bunches of important keys which are carried on the person should be insured with a key-insuring company. The company supplies a metal tab for attaching to the bunch. The tab bears the address of the company and offers a reward to anyone who finds the bunch and forwards it to the company. A number on the tab ensures the bunch being returned to its owner, whose identity is known only to the company .