Ivory
The yellowing everyone wants removed is the material ageing, and the conservation authority's instruction is to leave it. Almost every circulating method attacks a patina rather than a stain.
Precautions
- Test on an inconspicuous area first
In detail
Ivory is tooth material — dentine, with no marrow or blood vessel system, which is what distinguishes it from bone. It is porous, hygroscopic and it moves: CYCLICAL humidity change causes severe cracking and warping, worst in thin pieces like keytops. Ivory is one of the few materials here where the damaging thing is the environment rather than the cleaning. What the conservation institute permits is narrow and enough for a household. Dust with a soft brush toward a gauze-covered vacuum nozzle. If that is not enough and the piece is sound, ivory takes water and mild soap on a cotton swab: sparingly, a few square centimetres at a time, damp only A FEW SECONDS, dried at once, then plain water to lift the soap film. Never soak it, and keep water off cracked surfaces. THE YELLOWING IS NOT DIRT. The patina is natural ageing; the authority says no attempt should be made to remove it, and that sanding or bleaching will almost certainly cause serious damage. FRENCH IVORY IS NOT IVORY: a cellulose-nitrate imitation copying elephant ivory closely but lighter and more evenly coloured. Degraded, it emits acidic oxidising gases and in thin films has been known to combust spontaneously.
Properties
Sensitivity
- Acids
- Recorded
- Alkalis
- Not known
- Chlorine bleach
- Recorded
- Heat
- Not known
- Abrasion
- Recorded
- Porous
- Recorded
“Not known” means CleaningHQ has not established this, not that the material is unaffected.
Hacks and claims involving this
- Whitening yellowed ivory Does not work
Sources for this page
Sources
Care of Ivory, Bone, Horn and Antler — CCI Notes 6/1
Canadian Conservation Institute, Department of Canadian Heritage · Trade or professional body
Relied on for: That ivory is tooth material without marrow or vessels, that it is hygroscopic and cyclical RH causes severe cracking and warping, the permitted dusting and swab-with-mild-soap method and its never-soak rule, that the yellow patina is natural ageing which should not be removed, that sanding or bleaching will almost certainly cause serious damage, and that French Ivory is cellulose nitrate. (states this directly)
Verification: a person has read the passage relied on.
Read on — The whole note: Introduction, Identification (ivory and bone, walrus and elephant ivory, antler, horn, French Ivory), and Care (Handling, Storage, Cleaning, Illumination, RH and temperature). Supports the claim as stated.
What CleaningHQ cannot answer yet
These are recorded questions about this subject that we have not yet researched to a standard we would publish.
- Cleaning keytops safely, where the material may be ivory or plastic
- Identify a keytop material before treating it
Last reviewed by a person on .