In the 1920s, gramophones (wind-up phonograph players) were all the rage. These primitive sound machines used a sharp needle to trace the undulations of a groove spiraling around a flat disk that rotated under the needle mechanism. The changing position of the needle was mechanically amplified to produce audible sound vibrations.
The least expensive gramophone needles were made out of hard steel, which eventually wore out the records. Because they were inflexible, the steel needles also reproduced the micro-bumps made by tiny dust particles, adding undesirable noises called hiss and crackle.
The most expensive needles, which also produced the best sound, were made out of softer materials like pig bristles or carved bamboo slivers. These soft needles did not produce as much hiss and crackle as the steel needles and did not wear out the records. The very best needles were made out of the spines of prickly pear cactus (Opuntia), which are not only sharp and flexible but also very durable.
Tips for needle care in old phonographs: http://www.garlic.com/~tgracyk/needletips.htm
Listen to sound clips from old gramophone recordings: http://wap03.informatik.fh-wiesbaden.de/weber1/grammo/clips.htm