Saving Moldy Books, Family Papers and Wood Furniture: What Conservators Do First

By John Calhoun, owner of Mold Remediation Gettysburg PA · Updated October 29, 2026

Family keepsakes have a way of ending up in the basement or the attic: the box of letters, the old Bible, the photo albums, the dresser that came down from a grandparent. When those pick up mold, the first move isn’t scrubbing. It’s drying. The Northeast Document Conservation Center, which trains archivists and librarians, says to get moldy books and papers into a space below 55% relative humidity and under 70°F, and to freeze anything wet or actively moldy that can’t be dried within 48 hours. Solid wood furniture can usually be cleaned. Soaked upholstery and mattresses usually can’t.

The first hour: stop it growing

1. Move it out of the damp room. A dry room upstairs beats the basement every time. NEDCC’s target is below 55% relative humidity and under 70°F, checked daily. A cheap hygrometer tells you.
2. Separate the moldy from the clean. Keep affected boxes apart so you’re not spreading it.
3. Don’t brush or wipe yet. If the mold smears or feels damp, it’s active. NEDCC says to deactivate it first, by drying or freezing, before cleaning.
4. Decide what goes in the freezer. Anything wet or actively moldy that you can’t dry within 48 hours.

That 48-hour number shows up again and again. NEDCC’s wet-book leaflet says mold can start in as little as 48 hours, and that decisions delayed past that point mean faster damage. The EPA uses the same 24 to 48 hour window for drying anything in a house.

The freezer is a pause button

Freezing doesn’t kill mold. The National Archives’ guide for flood-damaged family papers says it makes mold dormant, which is why it’s useful: it stops the clock while you sort out a dry place to work.

Freeze these: wet books, wet papers and actively moldy items you can’t dry in two days. Wrap them in freezer paper, waxed paper or a plastic bag and freeze for at least 24 hours. Take them out of the plastic before thawing.

Don’t freeze these: old photographs and negatives, leather-bound books, and vellum or parchment, per NEDCC and the National Archives.

Dry it like a librarian

Point fans so the air moves past the books, not straight at them. Patience counts: NEDCC notes freezer drying alone can take several weeks to many months.

Cleaning once it’s dry and dormant

Dormant mold is dry and powdery. That’s when it can come off. NEDCC’s warning is the one most people learn the hard way: an ordinary vacuum will simply blow the spores back into the air. Use a HEPA vacuum, hold the nozzle just above the item, and for fragile pages, vacuum through a piece of fiberglass window screen held down with weights, or through cheesecloth over the brush. Do it outside or in a room you can clean afterward. For protective gear and anything about health, see the CDC’s mold pages.

NEDCC also suggests calling in a professional when more than about 100 items or 10 document boxes are affected, when the building or its HVAC is involved, or when things can’t be dried within 48 hours. Valuable or fragile items, like pastels, charcoal or flaking paint, belong with a conservator.

Furniture: wood yes, upholstery usually no

NC State Extension’s flood guidance draws the line plainly. For upholstered furniture, it may be best to discard it, because the padding holds water. For mattresses, it calls drying one thoroughly before mold grows almost impossible, unless it only sat in an inch or two of clean water for a few hours.

Solid wood is another story. NC State says mildew grows while the wood is above 20% moisture content, and suggests cleaning it with mineral spirits. Dry pieces slowly, out of direct sun, or they can warp and twist, and expect it to take weeks or months. That’s where a moisture meter earns its keep: I can tell you when a piece is actually dry instead of just feeling dry. The EPA’s advice for anything expensive or sentimental is to consult a specialist.

Where it should live afterward

The Library of Congress puts it bluntly: don’t store paper in attics or basements, because of the high risk of leaks and environmental extremes. It recommends keeping paper relatively dry, around 35% relative humidity, somewhere cool and stable.

That’s a hard rule in an old town. Gettysburg borough’s housing runs old (the Census Bureau puts the median year built at 1942), and older houses tend to have the damp basements and leaky attics the Library of Congress has in mind. In an old house, the basement and attic are often the only spare rooms, which is exactly where the Library of Congress says not to keep paper. The Gettysburg housing data page has both sets of numbers.

The real job is upstream

Every moldy box has a wet room behind it. Saving the letters is step one. Finding why the basement or attic got damp is what keeps it from happening again, and that’s my end of it. If the damage came from a flood or a leak, mold after basement flooding and keep it or toss it cover the rest of the house.

This is John Calhoun at Mold Remediation Gettysburg PA. If your stored things keep picking up mold, I’ll measure the room and find the source. Everything else I do is on the list of mold services, and how I approach a job is on mold remediation in Gettysburg, PA.