Used" is such an odd word, so much stranger than "second-hand." A prefix for condoms, and there's a certain squalor attached to the idea of reusing those.

Used books,” as if someone else has had the best of them and you get the sere husk, or the lees, as if a book isn’t the one thing, the one product, that is forever new. There’s no such thing as a used book. Or there’s no such thing as a book if it’s not being used.

Is there anything more plausible than a second hand?

It was squalor, absolute squalor. Bug infestations, trash on the floor.

I'm not used to interviews. People don't generally interview waitresses.

Your second-hand bookseller is second to none in the worth of the treasures he dispenses.