Clean Spark plug??

[Tedster]

So on Sunday I was inspecting my spark plugs, 3 of them had normal brownish color on the tip, the 4th was pretty clean on the tip, as you can see in the pics... why is that? Seems like its not getting used much or what? Car drives fine, good power... help. Thanks.
Both pics are of the clean plug.

http://i2.photobucket.com/albums/y37/mustafari/C01622.jpg

http://i2.photobucket.com/albums/y37/mustafari/C01619.jpg

[Tedster]

No one has any ideas??? :(

[Tzar177]

http://www.verrill.com/moto/sellingguide/sparkplugs/plugcolorchart.htm

[Protegebuddy]

Those look like bosch platinum plugs which you shouldn't run in your car.