The specimen degraded

Light

Pigments in wings, petals and feathers fade, and a display on a lit shelf is a continuous exposure. The 6 amber and 3 frosted containers on this shelf exist for the specimens that matter more than the display does.

Humidity, for dry material

Mold on a pressed plant and relaxing in a mounted insect both follow moisture. A sealed jar plus a desiccant is a cheap and effective answer, and the desiccant needs replacing rather than installing once.

Pests

Dermestids and clothes moths eat dry organic material, and they arrive with new acquisitions. A sealed jar excludes them, and quarantining anything new before it joins the collection is the practice that protects the rest.

Abrasion

A specimen loose in a jar grinds against glass whenever it is handled or moved. Mounting it so it cannot move is worth more than any other single decision for a fragile dry specimen.

And the fluid, for wet material

Level, concentration and clarity. A fluid that has gone cloudy or discolored is reporting something, usually incomplete fixation or material leaching out, and it is worth investigating rather than topping up.

Label everything, in pencil or alcohol-proof ink

A specimen without a label is a curiosity rather than a specimen. Inside the jar the label has to survive the fluid, which rules out most inks and most adhesive labels.

Inspect on a schedule you actually keep

Twice a year, with the date written down. Every failure on this page is slow, and the only thing that catches a slow failure is looking at intervals rather than when something goes wrong.

Quarantine anything new

A single infested acquisition can reach a whole cabinet, and the sealed jars that protect everything else are no help once something is inside one. A few weeks in isolation before a new specimen joins the collection costs nothing and prevents the one failure that is not slow.

References