My main worries were light scratches and corrosion (specially here in mallorca, where humidity is high) so to prevent them i just put the steelbooks in a sealing bag, then seal it with a pulse sealer and finally adding some heat with a heat gun closing it to vacuum.
Some pictures:
I spent about 50€ with the tools and 13€ for each bag of 100 sealing plastics. Hope in a few years the steelbooks remain in the same condition
