A stylus brush.
Your stylus works hard. It encounters dust and micro-debris each time you play a record.
Although stylus wear and need replacing over time, there are a few things you can do to help prolong the life of your stylus and maintain high quality quality sound from your set-up.
The most important thing to prevent accelerated stylus wear is to set your turntable up properly, especially the tracking force of your tone arm. Regularly cleaning the stylus, as well as ensuring your records are in a good condition and relatively dust-free will also go a long way to ensuring the longevity of both.
To use your stylus brush hold the tone arm steady and move the brush across the stylus a few times in the same direction that a record spins. This should remove any built up of dust and debris.