Jeepo23,
after a period of time, the Mic, Lightning port and loud speaker "Ports" (Holes) collect dust, debris much the same way as a person collects "Belly-Button fuzz" :)
You can use something like a toothpick, needle or ultra fine tweezers to try and clear out the debris it has collected, then use some high content isopropyl alcohol (95% or greater) to clean it up.
or follow the guide listed below to disassemble it to get to it better and try cleaning it up.
Personally:
For the trouble you would have taking it apart as described here:
[guide|29915]
It would be best to spend the $8.40 for a new Assembly and just swap out the bad/defective part listed here:
[product|IF268-004]