Aromatic repellant, the Mothballs!

In my childhood, one object drew my attention much by its smell! Even at these present days I could smell and detect its presence in any other materials that had contact with it: we can detect it by its characteristic aromatic odour - even when this odour is present in its lowest concentration! This object is white and round; and is commonly seen in households. It is nothing but our Mothball. Its content chemical is either Naphthalene or Para-dichlorobenzene. Its Tamil names are 'Mannenaikundu', 'Patchaa urundai', 'Anthurundai'.
It is used in cupboards to safeguard the stored dresses from the attack and damage by insects such as cockroach and silverfish. It usually, then contained Naphthalene, that is produced from either coal tar or petroleum; now it has Para-dichlorobenzene (deodorizer). It is peculiar to note that plants like Magnolias, termites and fungi also emit mothball-like smell - due the production of natural Naphthalene in them! With this they repel away insects and worms! Mothballs' content chemicals, when they are placed with dresses in a closed space, evaporate slowly into gas that kills the pests present and repels those trying to enter. But mothball can be harmful to children also, as it is taken by them mistaking it to be a candy; children swallow it as it is so attractive to them both by its appearance and smell.
These mothballs are still lingering to the households all these years, proving themselves to be wonder repellants, that were once the main sales article with peddling nomads!