Get new plugs, those are done for.
H9DCO from the dealer. $3/each.

----

It looks to me like the valve seals were leaking, it was fixed, but the plugs were never replaced. Do you have any oil consumption or history for the car?

__________________
2016 Monsoon Gray Audi Allroad - 21k
2008 Black Mercedes E350 4Matic Sport - 131k
2014 Jeep Wranger Unlimited Sahara - 62k
2003 Gray Mercedes ML350 - 122k