Eenis

I threw a P0302 code over the weekend, so I changed my plugs this morning. a few things about the guilty plug threw me for a loop.

1. When I went to remove the spark plug, it seemed loose. Not a biggie.
2. Something in the spark plug failed, as I can turn the plug upside down and the center electrode will slide further into the plug, and right side up the center electrode will slide out until it rests against the ground electrode.
3. Somewhere between the plug being loose and some kinda construction breakdown, the chamber now has a bunch of grime in it. Y'all should have seen the coil pack.

So my questions are:
A. Has anybody seen a plug do that before? If so, what causes it? Incredibly curious.
B. What's the best way to clean the chamber out, if I even need to clean it at all?

FYI, was running NGK copper plugs w/ about 35k on'em (had been planning to change anyway...code made me do it). and my ses code is gone!