A small art storage room collects more than art. In a gallery back room or a collector's spare closet, extra mats, empty crates, rolls of glassine and old catalogs pile up. There may be a tray of crackers from the last opening. To a mouse, that's a house with a pantry.

Cleaning a room and caring for art are different jobs. A watercolor or a gilded frame is not a countertop. Split the problem in two. One job is the building, keeping mice out and finding how they get in. The other is the collection, and once mice have reached the objects, that part belongs to a conservator.

What mice want from a storage room

The Canadian Conservation Institute ties rodent activity closely to available food. Mice also want water, nesting material and shelter, and a quiet storeroom can offer these. Their front teeth never stop growing, so they chew things they don't eat. They shred paper and fabric for nests and leave urine and droppings along their routes, soiling whatever sits in the way.

Art adds its own menu. The institute warns that objects containing starch, protein or fat may be eaten, damaged or carried off. Dead mice and droppings can also draw insects that feed on protein, and those insects may move on to the art.

Treat the building as the outer box

The building is your first barrier, and the cabinets inside it are backup. Walk the edges of the room and look wherever pipes, cables or ducts pass through a wall or floor. Check the gap under the door. Look for holes someone stuffed with crumpled paper, since a plug a mouse can chew through isn't really a plug. Make these checks part of the building's normal upkeep, not a single afternoon's project.

Keep snacks and trash out of storage entirely. Yes, that means the mints in the desk drawer too. After an opening, don't leave catering leftovers or trash bags near the storage door. The institute describes mice settling into a gallery kitchen near event spaces, far from any stored art, a reminder that food anywhere in a building draws mice.

In pest work, sealing a building against rodents is called exclusion, and knowing a few terms like that makes talking with a contractor easier. The guides at RodentExterminator.com explain rodent species, signs of activity and how exclusion works. Its listed service areas are in Texas, and its pages deal with buildings, not art, so object decisions stay with the conservator.

Make the room easy to inspect

You can't respond to what you can't see. The institute advises giving staff easy access and avoiding blind cavities. In a small room, choose shelving on legs so the floor underneath stays visible. Leave enough space behind shelves to shine a flashlight along the baseboard. Don't lean crates or frames against walls where nobody looks. Keep spare cardboard, tissue and bubble wrap in closed bins, since loose packing makes easy nesting. Cabinets with tight doors add one more layer.

Keep a simple log

A notebook by the door is enough. Whenever anyone spots droppings, gnawed edges, shredded paper or greasy smudges along a wall, they note the date, the place, what they saw and what was done. Over time the log shows whether trouble keeps returning to one corner or whether a repair worked. The institute says paper records are fine and urges making reports easy.

Housekeeping and rodent waste are different jobs

Dusting shelves and picking up packing scraps in a clean area are routine chores. Droppings, urine stains and nests are not. The CDC warns against sweeping or vacuuming rodent waste. Doing that can put tiny droplets carrying viruses into the air, and breathing contaminated air is the main way these diseases reach people. Keep the broom and vacuum away from any spot mice may have used.

If you find signs near the art

Stop handling the objects in that area and keep other people out of the room. Don't wipe, spray, freeze or wash any artwork yourself. Instructions for disinfecting a floor don't tell you how to treat paper, paint or gilding. The institute also advises breathing protection and protective clothing for anyone cleaning infested material.

Then bring in two kinds of help. A qualified pest professional handles the building, finding how mice got in, removing them and closing gaps. A conservator handles the objects and decides what can be cleaned and how. A pest service isn't the one to judge whether a pastel can be treated.