One of the students recently blew our minds when she came back from an internship and told us that you can wash and re-use smoke sponges. They're vulcanized rubber blocks designed for removing soot from walls after a fire, a pretty similar application to removing surface dirt from paper, so we've adopted them in conservation for that use. Only I was taught to cut them in increasingly smaller blocks to expose new surfaces as the old ones get dirty, until I'm left with a pile of tiny black sponges that just can't be cut anymore. There's an art to this as well, because of course the thing squishes between the scissors, making it difficult to cut a flat plane. Each new smoke sponge is a game to cut into the most efficient bits possible. Used to be a game.
The student learned on placement that all you need to do is wash the sponge in soapy water in order to make it pretty close to clean and reusable many more times! No more careful cutting, no more holding onto tiny bits of sponge. I was so incredulous that I ran off and did it right away, and then felt pretty stupid for not having thought of it before. Rest of the world, did you know this and not tell me, or is this going to blow your mind also? Check it out: