[overkill]

Ok, Im going to replace the cam tensioner on the car, the engine oil, and the spark plugs. Now, for spark plugs I got the bosch 4 tip plugs. The engine oil, I got Mobil1 15w-50.

First, I just removed the park plugs and I noticed that they were all considerably clean. Except that the plugs for cyclinders 3 and four had some oil of them. Now, the oil was on the threads fartherest from the firing tip. Now, the tip of the plug was just black, there was nothing caked on it or damage, no white deposits,... basically according to the haynes manual, they are normal. Now, how would there be oil on just the thread portion of the plug? There wasnt alot of oil either, just alittle. Plugs 1 and 2 had nothing on them. Whats up?