The VHS Tape
Designing the mysterious VHS tape to look like it had 1) been inside a camcorder under thick underbrush deep in a forest for 28 years, and 2) been gently cleaned by the girl who found it was not easy. There are design concerns to be sure (and I should have left this to Megan, our brilliant production designer, but--well, I didn't), but the most difficulty came from the fact that VHS cassettes are nearly indestructible.
There's our tape, in new condition (what's recorded on it will forever be a secret; that's life, get over it). I topped a pyrex dish with foil, and floated the tape on the foil so that it wasn't sitting directly on the glass. Then I put it in the oven:
4 minutes at 350 degrees should be plenty. We want slight warping; too much would be unsuitable for our story.
It came out with subtle warping in some areas:
Then I soaked it in Los Angeles tap water filtered through pipes that probably haven't been cleaned since the 70s. And then I put it outside and left it there for weeks.
Over that time, this marvel of technology suffered the brutal Los Angeles sun and acid rains. I also buried it in the mud, cleaned it off, drenched it with bleach, brass cleaner, Old English scratch remover, and Drano (not all at once; I'm no chemist, but I'm pretty sure there would be some kind of fatal reaction here). Defeated, I left it alone for a while longer.
A little better. So I packed it up in a box full of other things and shipped it to Missouri, where I will be in about a week.
(If this had been set in 2040 and the technology in question had been a CD, this wouldn't have been difficult at all. Say what you want about obsolete formats, but these shells are tough.)