Remove dust or lint from charging port?

Try using a clean small brush, something like a soft toothbrush might do, and gently brush to remove the lint. If there is an excessive amount of stuff in there try a small wooden toothpick and gently prey the lint loose.

Use a 'static free brush' when cleaning out dust by using a non static brush you generate static electricity that could easily mean the death of your system. Do not use a vacuum cleaner too. At the Apple store I have seen static free brush for sale. Don't know how much it is and you can call Apple store to find out.