Cleaning charging port

Maybe a tiny computer components cleaning brush and/or a small piece of a lint free or microfibre cloth and move it around in the port.

Electronics and liquids/dried liquids and powders do not mix.

That iPad maybe on borrowed time before the port and/or the entire iPad stops working.

Sorry & Best of Luck to You!

Cleaning would be best entrusted to the technicians at the Genius Bar of your local Apple Store, or Apple Authorised Service Provider (AASP):

Genius Bar Reservation and Apple Support Options - Apple