Oil on Spark Plugs?

Hello everyone. I was changing out my spark plugs and noticed oil. What does this mean??
Thank you!

 

Looks fairly normal to me, the dark deposits on the threads are just from combustion gasses seeping by.
As long as there is no oil down in the tubes where the plugs sit your fine.

 

That tiny bit of oil on the threads means nothing. The tip is clean and normal looking just badly worn.
Change the plugs and truck on...

 

Unless it was fresh oil, I wouldn't worry about some discoloration after 60-100k miles.

 

Just changed them today. Looked like they were originals at 120k miles since there were both NGK and denso plugs present.

thanks guys!

 

Same here on my 2014. I changed mine out a few months ago. I knew they had been changed previously at 15,000 at a dealer but no record after that of any changes. This meant with the current mileage on the truck, they could possibly have had approx 115,000 miles on them when I changed them. Six OEM Denso in about the same state of wear as yours. The threads looked like yours, with no blow-by and no oil on the insulators. (dry tubes) Also telling is that the truck didn't feel any different to driving it with the brand-new plugs, but it may start a little quicker now, and the gas mileage may have improved.... but not by much.

[EDIT] Spark plug trivia tip I learned recently: If the spark plugs have a number stamped on the metal tip/terminal of the insulator, they are the original plugs from the factory installed when the engine/truck were built. OEM Toyota replacement plugs (in my case Denso) do not have numbers on the terminal.