In their battle against time, archivists have picked up a new weapon to bring back old manuscripts: dry ice.

One of the big problems in preserving papers, or getting a closer look at old, salvaged papers has been figuring out how to get beneath the grime of history to what’s waiting below. Obviously, the old standards of soap and water are far from ideal for cleaning paper. So what does an archivist do?

Commenter BuckCaldwell explains how that same tech that NASA scientists are using to clean telescope mirrors is also getting used in libraries:

I’ve seen this done on books and other (very old) paper materials. Essentially sand-blasting with dry ice. Since the dry ice is softer on Mohs scale than the paper or the ink, and sublimates immediately upon impact to gas, it doesn’t harm anything, but the energy of the impact and sublimation will dislodge dirt from the surface. Fascinating stuff one never thinks about. Kudos who whoever thought it up.


And it’s not just for documents dirtied-up by time; it can also clean up paper from much more recent encounters. After a fire swept through Utah’s historic courthouse in 2006 (which also doubled as a storage chamber for its 200-year-old collection of documents), the technique was also used to get the soot and smoke out of the pages and canvas.

Image: Ivo Petkov / Shutterstock