Specialized websites provide appropriate information, but here is some practical advice.

The main enemies

• dust: it clogs up filigree or engravings, it is also harmful to kingfisher feathers: it severely reduces their brightness.    

• insufficient humidity: dryness causes cracks in shell, horn (photo 2 - photo 3), ivory or pearl. 

• sudden temperature changes: they are fatal to glass beads (photo 4 - photo 5) for example which burst, they also cause damage to celluloid whose chemical composition is not stable. 

• exposure to light: it destroys celluloid which sometimes breaks or simply starts to melt. Here are BEFORE and AFTER (7 - 8) photos that say  a great deal.

• exposure to air: it oxidizes metals such as silver or brass 

 lack of ventilation: a minimum is required for celluloid, and generally all living materials. 

• plastic packaging: their chemical substances can produce damage, for example to mother of pearl. 

• vermin infestation: clothes moths have a devastating appetite. They cause damage beyond repair. They especially love shell and horn and start eating the dirtier parts such as the tips of teeth on combs.

Wood and vegetable fiber is also much appreciated by insects such as weevils.

Dusty kingfishers feathers
Too much dry horn becomes fragile.
Twisted teeth due to bad stocking
Damaged glass beads due to sudden temperature changes and shocks
Damaged glass beads due to sudden temperature changes
Celluloid comb, before degradation
Chimical degradation due to light and hot temperature
Close up of degradation: discoloration and cracks
Damaged teeth due to weavils attack
Damaged teeth due to rough use