A cigarette is a narrow cylinder containing burnable material, typically tobacco, that is rolled into thin paper for smoking. Most commercial cigarettes contain a reconstituted tobacco product known as sheet, which consists of "recycled [tobacco] stems, stalks, scraps, collected dust, and floor sweepings", to which are added glue, chemicals and fillers; the product is then sprayed with nicotine that was extracted from the tobacco scraps, and shaped into curls. The cigarette is ignited at one end, causing it to smolder; the resulting smoke is orally inhaled via the opposite end. Most modern cigarettes are filtered, although this does not make them safer. Cigarette manufacturers have described the cigarette as "a drug administration system for the delivery of nicotine in acceptable and attractive form."