Busan sits on the coast, and coastal humidity affects more than laundry drying times. Holders who store steel seed backups in home safes near exterior walls sometimes discover faint oxidation during reviews — not enough to destroy legibility, but enough to warrant attention.
Material differences
Stamped steel plates resist corrosion better than engraved aluminium in our experience. Ceramic tiles survive humidity but crack under impact. Choose material based on where the backup lives, not just upfront cost.
Location within the home
Interior closets on upper floors tend to stay drier than ground-floor storage near the street. Avoid bathrooms and kitchen cabinets where steam concentrates. If you keep a backup at the office, note whether the building runs dehumidifiers overnight.
Rotation as a habit
Some holders maintain two steel copies in different locations and inspect each during alternate annual reviews. This spreads risk and gives you a comparison point — if one plate shows corrosion and the other does not, the storage environment is the likely cause.
What to record
During your checklist session, photograph each plate in consistent lighting and note the storage container type (silica gel present or absent, sealed bag or open shelf). These details help you spot changes year over year.