Follow this guide to make a custom cotton swab.

You can also use dental picks with barbed tips (non-flavored).

You can use a normal cotton swab, but most are too thick and have loose cotton that can snag on sharp edges.

Apply a few drops of highly-concentrated isopropyl alcohol (>90%) to the cotton.

Insert your tool in the charging port.

Don't force the tool in and out of the port, as you risk damaging the contacts or getting cotton wedged in the port.

Rotate the tool around the perimeter of the port to clean it.

Wait a few minutes for the isopropyl alcohol to evaporate before plugging in your device and testing it.