Add a few crystals to a small bowl of very hot (not boiling)  water.A powerful vapour is produced.

Menthol is included in many products for a variety of reasons. These include:

In non-prescription products for short-term relief of minor sore throat and minor mouth or throat irritation
Examples: lip balms and cough medicines
As an antipruritic to reduce itching
As a topical analgesic to relieve minor aches and pains such as muscle cramps, sprains, headaches and similar conditions, alone or combined with chemicals like camphor, eucalyptus oil or capsaicin. In Europe it tends to appear as a gel or a cream, while in the US patches and body sleeves are very frequently used
Examples: Tiger Balm, or IcyHot patches or knee/elbow sleeves
In decongestants for chest and sinuses (cream, patch or nose inhaler)
Examples: Vicks Vaporub, Mentholatum
In certain medications used to treat sunburns, as it provides a cooling sensation (then often associated with aloe)
As an additive in certain cigarette brands, for flavor, to reduce the throat and sinus irritation caused by smoking.
Commonly used in oral hygiene products and bad-breath remedies like mouthwash, toothpaste, mouth and tongue-spray, and more generally as a food flavor agent; e.g. in chewing gum, candy
In a soda to be mixed with water to obtain a very low alcohol drink . The alcohol is also used to alleviate nausea, in particular motion sickness, by pouring a few drops on a lump of sugar.
As a pesticide against tracheal mites of honey bees
In perfumery, menthol is used to prepare menthyl esters to emphasize floral notes (especially rose)
In first aid products such as "mineral ice" to produce a cooling effect as a substitute for real ice in the absence of water or electricity (Pouch, Body patch/sleeve or cream)
In various patches ranging from fever-reducing patches applied to children's foreheads to "foot patches" to relieve numerous ailments (the latter being much more frequent and elaborate in Asia, especially Japan: some varieties use "functional protrusions", or small bumps to massage ones feet as well as soothing them and cooling them down).
In some beauty products such as hair-conditioners, based on natural ingredients