What is one method of ingestion commonly used for inhalants?

Inhalants are substances that produce chemical vapors which can be inhaled to induce a psychoactive effect. One common method of ingestion for inhalants is to spray them into an empty soda can to create a makeshift inhalation device. This method allows users to concentrate the inhalant vapor in the can's space and then inhale the vapors directly from it, facilitating a more intense and rapid intake of the substance. The choice of an empty soda can is practical because it is readily available and can be used discreetly.

Other methods of ingestion, such as the ones mentioned in the other options, do not align with how inhalants are typically consumed. For example, injected substances are usually associated with drugs rather than inhalants, and swallowing in pill form is not a common method employed for these particular substances. Smoking from a pipe relates more to substances like tobacco or marijuana rather than inhalants. Thus, the use of an empty soda can exemplifies a distinct and prevalent method for inhaling vapors from volatile substances found in various household products.