Well almost... I swap my plug pretty regularly so it will always be fresh.  To freshen up a plug and make it new again, I use a pneumatic spark plug cleaner from Harbor Freight Tools (http://www.harborfre...emnumber=32860).  

I learned this trick back when I was a kid hanging around 'real' mechanic shops. I two or three second blast and my oily plug looked like brand new!  The plug cleaner can make a fouled plug work again, and older plugs can be kept in the toolbox or fanny pack as an emergency spare for your bike or someone else's.