There is a lot happening in these tins. From a conservation point of view, we are dealing with corroded metal tins; acidic and stained card; acidic, yellowed, brittle and crumbly glue; surface dust, ingrained dirt, and possibly aged pesticides.
And last, but not least, partially degraded insects. Some beetles have already become detached from the card while others are missing legs, heads, or antennae.
Beetle in middle during cleaning under microscope, left side of body already cleaned. Karin Konold (June 2017), Auckland War Memorial Museum - Tāmaki Paenga Hira