I bound the book with sewing thread, and I tried to dye it with a teabag. The teabag was twice-used before I got to it, so it didn't really work for aging the paper. All I got was a sopping wet chunk of book. I brought it upstairs and ran it over with a thin amount of brown watercolor, and I think that worked great. The brown soaks in just the right amount if the paper is already wet.
Here's the inside:
For the inside, I just basically made scribbles that looked like words and drew alchemical symbols every few pages. I also crossed things out and added arrows. After all, it is annotated by the Half-Blood Prince.