As much as I like to imagine that library books remain perfectly clean, the reality is a little different. Sometimes books get gunky. Oil from people’s skin rubs off onto them. Someone spills a cup of coffee on a book cover. A child drops her novel in the garden. In cases like these, libraries have to put a little work into cleaning the reading material.

On April 20, 2017, the Boston Public Library tweeted a video of their ingenious machine that helps them clean books. (You can see the video below.)

The machine is known as a Depulvera, and it really does look a bit like a car wash. Books are set on its conveyor belt and are…