Now don’t be grossed out, but this is part of what I found in my iPhone 6 lightening port last night. My charging cord wasn’t fitting securely and I was worried that I might have a loose connection in the phone. After confirming a suspicion with a flashlight that lint-crap was causing the connection problem, I fished this out with some tweezers. It’s not a lot, but enough to keep it from charging.
Keep your ports clean.