Belly lint forms when your clothes rub against your stomach and falls into your bully button. AnswerParty!
Lint is the common name of visible accumulations of textile fibers and other materials, usually found on and around clothing. Certain materials used in the manufacture of clothing, such as cotton, wool, and linen, contain numerous very short fibers bundled together. During the course of normal wear, these fibers may either detach, or be jostled out of the weave of which they are part. This is the reason that heavily used articles like shirts and towels become thin over time, and why these particles collect in the lint screen of a clothes dryer. Because of their low surface area, static cling causes fibers that have detached from an article of clothing tend to continue to stick to one another, and to that article or other surfaces with which they come in contact. Other small fibers or particles also accumulate with these clothing fibers, including human and animal hair, skin cells, plant fibers, pollen, dust, and microorganisms. The etymology of the modern word "lint" is related to "linting", the term used for the cultivation of the shorter fibers from the cotton plant (Gossypium), also called "lint", from which lower quality cotton products are manufactured. Lint is composed of threads of all colors which blend hues and appear to be a uniform grey.