When I began storing my painted minis in A4 printer paper boxes some years ago, it soon became apparent that the minis - especially those of a metallic disposition - needed sometning to hold them in place when moved around.
At the time, I almost exclusively based my minis on slottas (silly me!), and the logical solution seemed to be magnets.
Neodynium magnets, AKA rare earth magnets, AKA super magnets, come in all sizes and shapes, and I found that 2 mm thick discs fit nicely in a standard 25mm slotta.
In the beginning, I then started switching to metal cookie bins for storage, as the minis with magnets in the base would cling nicely to the bottom (or side, or lid, for all that matters). Soon I realized that this was impractical, due to the shape of the bins (round), and the fact that they are very smooth on the outside, and easily slip - causing stacks to topple over.... NOT good.
Instead, I switched back to the paper boxes, now buying A4 magnetic sheets to put in them. This works a treat, and the boxes stack neatly and safely.
Since then, I have begun basing all minis with integral bases on steel washers, and they adhere nicely to the magnetic sheets, too, and I happily kept buying expensive magnets to glue into the slotta-based minis.
Until it struck me: I do not need morto magnetize the minis, as long as the base is either steel/iron, or contains sufficiently of it for the magnetic sheet to attract!
I then remembered, that when making chainmail hauberks for LARP, I used iron thread (for fences) 2,04 mm thick. Cut into pieces, it can be glued into the slottas, on top of thin cereal package material (to make it touch the surface of the magnetic sheet.
To the left you can see an example of a slotta with a magnet, and one with pieces of iron thread.
The iron thread comes in rolls of about 200 meters, and such a roll will last me for years, even as I'm going to put iron in the bases of all my painted LotR minis before using them for SAGA in tyhe near future.
The head? I don't know, found it in the wreckage after the storm, lately... ;o)
I have started using Locktite Power Glue gel to glue minis to bases (and stuff under the base), btw... This method results in a much stronger join (and a tighter fit) than using thin super glue.