Years ago, when I did issue 15 of the original TMNT comic book series, I wanted to tweak the cover to make it look like an old comic book which had "been through the war", as they say. I penciled the art, created a new logo, and designed the cover in the style (or at least my approximation of it) of the classic "Golden Age" superhero comics. Ryan Brown did a fabulous job inking it, incorporating a lot of that "Golden Age" flavor.
Steve Bissette told me about a copy shop in Wilmington, VT which could print color art on slick paper. I had them make a couple of copies from my hand-painted art, then left one of them on the floor of my car for several weeks to begin the "distressing" process. Later I enhanced it with judicious tearing and application of "coffee" stains (actually brown ink), scotch tape, and so forth.
Here's the cover as printed:
And here is the "clean" art, as it looked originally. I don't think this has ever been printed anywhere. -- PL