How to eliminate all colors except one in a drawing?

I made a drawing with plain old pencil and paper. I then scanned it, and subsequently loaded it into Photoshop. Using Photoshop's pencil function I drew over the scanned image, making a black outline drawing of the scanned image.

Now, I want to remove ALL the colors and shades of gray that were scanned, and leave ONLY the black line drawing that I made with photoshop.

Basically, is there any way for me to basically "protect" the black in my image and turn everything else in the image white?

Dr.Nebula...

Are you SURE you want ONLY fully black pixels representing your lines? I'm going to assume for the purposes of this query that you know this will create jagged, aliased lines at any resolution under about 600 ppi.

Not to be mean but it seems like the amount of time spent on this you caould have retraced the image on another image and been done with it. But at least you know what to do if you forget to put it on a seperate layer again.

Josh,

Not knowing the complexity of the image, I don't see how you can say it could be retraced in 45 seconds---and I type with one finger!! :-)

What's more, you have to look beyond the stated problem to the ramifications and potential new approaches to other problems blossoming from an unusual solution to this admittedly mundane scenario.

George