One overlooked step in storing electronics is condensation cycling. Basically put the unit in a plastic bag, being careful to assure that rain won't be able to pour in. When doing this, its best to pack it on a dry day so there is less humidity inside.
It doesn't take a lot of air cavity to hold enough humidity to condense on electronics when the temperature cycles down into the cold range. To do it the best, fill as much of the cavity space with filler like closed-cell foam or styrofoam. Blocks displace more air completely than those shipping styrofoam "peanuts" but the latter can fill the odd remaining spaces. Open-cell foam that is more available really isn't much help. The less free air cavity inside, the less condensation issues you'll have inside the bag.
Some would say that putting in absorbents is enough, and that would be true until they become saturated. As vintage electronics tend to be stored a lot longer, its better to reduce the air volume inside.
One trick I've used is to save shipped boxes that have styrofoam liners like the ones I get from the "Honey-Baked Ham" company. They're particularly good because they have a solid 5-side piece with a fitted lid. I bag items inside and put the styrofoam lid on them and *then* slide the cardboard box down over it so that when the box is sat in its normal orientation, contents are inverted and the solid piece of styrofoam make a protecting cover over the contents. It helps insulate and protect shoud water ever soaks the box; the styrofoam lid at the bottom assures it won't collect water inside the styrofoam.
I've boxed up my old BYTE magazines this way too except due to the summer heat I wrapped each stack of magazines in cut-outs from old blankets because I didn't want to risk the plastic bag melting to the magazine covers.
If you think there is not enough air inside a case to form condensation on surfaces, I once had to diagnose and solve a problem for a company that thought they had a software bug. In fact the problem was that inside their 3x4x4 inch sealed case, there was enough air that condensation formed on the board and because they were cheap and stupid, they didn't pay for soldermasks on the printed circuit boards as so droplets formed on the leads and traces of the crystal, it made the microprocessor crazy. It didn't help that their manufacturing site had no temperature or environmental controls and the problem was worse on days when it rained.
The solution was to immediately silicon-coat those traces which removed the "bug" and later to order proper printed circuit boards and to insert a block of styrofoam into the cavity to reduce the air volume so that condensation would be insignificant.
