How to stop oil from coming inside spark plug no#3 cylinder? on 1992 Honda Civic

Is there any other ways besides removing head cylinder or pulling all the valves, rocker arms and all bolts from the shaft, etc...every week i checked that spark plug,an oil about 1/2 inch inside. it's not overheating but causing little misfire and affected the gas mileages per gallon. original engine only 112k miles. thanks

Asked by for the 1992 Honda Civic
What does compression test show? Ring or valve problem?
i will check compression monday. ring or valves i do not know but visible problem is spark plug soaked with oil. in your knowledge of Honda engines what is the possible cause?
I'm guessing cracked head or worn valve guide.How bad is the misfire? Put a vacuum guage on it see if it stays steady or fluctuates.
thank you for the response i found the problem.
well, what was it?
deep well o-ring