Maintenance
Part of Why do the same archive mistakes keep happening to careful people?
Cleaning: the archive mistake that does the most damage at home
Why cleaning is the most damaging thing a beginner does, what liquids actually do inside a layered object, and what to do instead when something is wet.
What to take away
- Cleaning looks reversible and is not. Liquids do not stay in the layer you applied them to.
- Dust removal by mechanical means is a different activity from cleaning with any liquid.
- Water is not a mild option. On layered objects it is one of the more damaging ones.
- When something is wet, the decisions are about time and air, not about cleaning agents.
Why cleaning is the classic beginner mistake
It is the most satisfying thing you can do to an object and the least reversible. The Canadian Conservation Institute's note on cleaning paintings and its precautions is written about paintings and the reasoning applies to almost anything layered, which includes photographs, coated papers and varnished objects.
How liquid damages layered objects
- Liquid applied to surface
- Penetrates cracks and capillaries
- Reaches all layers underneath
- Soluble ground layer weakens
- Attachment to support fails
- Flaking begins immediately or later
It says plainly that cleaning a surface may appear straightforward.
It warns that untrained individuals should not attempt to remove layers of dirt and discolored varnish. Accurately judging what a cleaning agent will do requires understanding the materials in every layer and extensive practical experience.
The mechanism is the part that persuades people. Applying a liquid or paste rarely affects only one layer: liquids can penetrate all layers through visible and invisible cracks and capillaries. So the effect has to be considered not only against the dirt and the surface, but against everything underneath.
Its water example is the one to remember. Water applied to an object with a soluble ground layer can weaken that layer's attachment to its support, producing immediate or eventual flaking. If enough water reaches a fabric support, which is especially water-sensitive, the fabric shrinks, separating the layers and distorting all of them.
Nothing about that is specific to paintings. A photograph is a gelatin layer on a paper or plastic support, and it behaves the same way.
What you may safely do
- Remove loose surface dust with a soft brush, working away from yourself, on stable material only.
- Vacuum a shelf or the inside of an empty box, never the object.
- Support and enclose. Most apparent dirtiness is dust that will not return once the item is boxed.
- Photograph the condition and leave it.
And what to leave alone: anything flaking, powdery, tacky, actively moldy, or with a surface you cannot identify.
Safe actions and leave-alone list
- Remove loose dust with soft brush
- Work away from yourself
- Vacuum shelf or empty box only
- Support and enclose the item
- Photograph condition and leave it
- Leave flaking, powdery, tacky, moldy items
Why the urge is so strong
It is worth understanding rather than just resisting. A dirty object looks neglected, and cleaning it feels like taking responsibility for something a previous generation let slide. That instinct is doing real work elsewhere in this job, and it should be pointed at the room instead.
Redirect it. Clean the shelf, not the photograph. Replace the enclosure, not the surface. Improve the conditions, which is the one intervention that helps every item in the box at once and cannot be done badly enough to destroy anything.
When something is wet
Wet is an emergency with a clock on it, so the correct response is drying and air, not cleaning. Michigan State University Libraries' page on disaster recovery for media collections is a good model for preparation.
What soaked the item?
What liquid soaked the item?
Clean tap water -> dry and air, time to act
Dirty water or seawater -> contamination and salts damage while drying
Its own media preservation unit created printable checklists, one for optical media and one for video cassettes, kept at workstations for quick reference.
It also points to guidance summarizing recovery procedures for modern information carriers after immersion: compact discs, magnetic diskettes and magnetic tapes.
The guidance distinguishes between tap water, seawater and dirty water, because what soaked the item changes next steps.
That distinction is the useful transfer. Clean water buys time. Dirty water and seawater do not, because contamination and salts do their own damage while the item dries.
Print the checklists you need now. Nobody researches procedure at two in the morning with a burst pipe.
Our guide to what actually damages a home archive covers the causes, and the notes on damage that is hard to undo cover the other irreversible actions.
