I wonder how well that worked for him? If I saw some books on someone's shelf that had black spines, I'd be very curious about them.
I recently picked up a large lot of vintage paperback smut and about 2/3 of them had the spines completely blacked out.Link
Looks like the owner lined them up and hit 'em with the spray can. I guess he didn't want to broadcast his reading taste to the world...like people are going to assume blacked-out mass markets are Remembrance of Thing Past or something.
I've seen a lot of interesting things done to these books. Necklines raised with magic marker, pasties drawn on, 3/4 inch staples through the open edge, it's a shame but the varied attempts at censorship are fascinating.