Pictures with watermark

There are a few pics here on danbooru i've found with watermarks on them (by people who are obviously not the original artist). If i have these pictures WITHOUT the watermark, what should i do? Should i upload the "clean" version?

Yes, and flag the watermarked copy for deletion after setting the clean version as its parent.

So basically

1: Upload clean pic
2: Edit old pic and set the new pic as the parent of the old pic
3: Flag for deletion?

That is correct, sir.