I have a 1986 mercruiser 170 and I noticed lot of rust around the spark plugs. I ran my finger around the plugs, I believe that is called sparkplug well, rust debri comes out. It comes off even when I scratched with bare finger. I took the plugs out and there is no rust inside. My concern is that some of the debry will fall in when i put in the new plugs. Any ideas on what is the best way to clean that rust and secondly how to prevent it from getting worst. I would have used a wire brush but it wont fit in there, it is a pretty tight place, just hoping some of you may have some creative ideas.