Which type of item is typically utilized as a filter in heroin preparation?

The use of cigarette filters in the preparation of heroin can be attributed to their effectiveness at filtering out impurities during the process of dissolving the substance. When individuals prepare heroin for injection, they often mix the drug with water and heat it, and a filter is needed to remove any insoluble materials that may have been present in the heroin or introduced during the preparation process.

Cigarette filters, being made from fibrous materials that can catch particulates, serve this purpose well. They are relatively accessible for users and can be easily integrated into the setup for preparing a shot. This is why the option regarding cigarette filters is considered correct, as they play a practical role in the dilution and preparation process commonly associated with heroin use.

While cotton swabs could conceivably serve as a filter, they are not commonly associated with this specific use in the context of heroin preparation. Pill containers have no relevant function in this aspect, as they do not possess filtering capabilities.