You can find them in department stores or supermarkets. Choose a type with a low ruffled tip so that the cotton yarn does not get caught inside the jack. The small tip cotton swab will easily get inside the jack and clean more effectively.
Pick a cotton swab in the jack. Be careful not to jam the tip of the cotton ball in the jack. You need to push the tip of the cotton swab into the hole gently until the tip is deep in the jack. Rotate the toothpick to clean the nooks and crannies inside the jack. After you pull out the cotton swab, most of the dirt will fall out.
For stubborn debris, you can dab a little rubbing alcohol on the tip of a cotton ball. You need to dip so that the cotton swab is just damp, not soggy or dripping. Remember to wring out the cotton ball, then insert the tip of the cotton swab back into the jack and rotate.
Dry the jack with a clean cotton swab. The rubbing alcohol will dry quickly on its own. However, you should soak up any remaining moisture to minimize the surface’s contact with the solution. Insert a clean cotton swab into the jack, let it sit for a bit, and then rotate it back and forth to absorb the alcohol.
Note that when cleaning the 3.5mm jack or cleaning headphones pads, you should be gentle to protect the product from damage or scratches. Good luck.