For those asking about magnets, I've got a good tip that also include recycling.
With all of the personal data theft, you should never throw away an old hard drive. Even if you wipe it, it should be recycled.
Well, here's what you do. Before you take it to the recycling center, open it. Inside you will find 2, VERY STRONG magnets. These magnets are welded to flanges that have holes in them to keep them screwed to the inside of the case.
Not all of them can be re-used and they can be a pain to get to. But, once you do, I just mark where the holes are on the bottom of my cache container, drill holes, and attach them with bolts (Using nuts, lock washers and a little JB weld on the threads to keep them in place).
My Micro 209 cache is one such that I used a single, small Hard drive magnet on the bottom of an Altoids mini tin.
Strollin' With Trolls is also made this way, but with a larger mint tin.
(There are images on both Cache pages)
I've thought about useing 2, maybe 3 of these larger ones to turn a 30 or 50 cal ammo can into a magnet cache!!!!
I have a box of about 15 of these and will be recycling some more drives soon. I've started keeping a couple attached to an old wrench I stick in my back pocket and leaving them in Caches for other people to take and use for their own.