Cases protect from impact but do not correct a bad environment
A case can reduce dust and accidental damage, but it does not automatically make a room that is too damp, hot or prone to condensation safe.
Store the item dry and do not close damp cloths, damaged sachets or materials that can transfer substances inside with it. Periodically check for odours, mould, corrosion or changes in the case itself.
Foam, adhesives and internal linings can also age; if they begin to crumble or become sticky, avoid prolonged contact with the gear.