How do i remove a spark plug that is just spinning removed first three ok last one was loose and just spins wount tighten or slacken off bike was running fine before winter thought i would give plugs a clean and came across this.

you can place a mirror to reflect whats going on inside the plug hole. maybe something is happen to the plug thread. in my case before, the previous owner had put a black tape to the plug thread, so when the engine gets hot, the tape melt in the thread and I can't get the plug out. what i've done is to remove the melted tape first then the plug.

could that the plug faces have rounded off so the plug sockets not getting a grip? i had that problem and i put a slight bend into the socket faces with a hammer and screwdriver so that it got a better grip.