Several years ago with the introducton of NIMS (National Incident Management Syetem), I took classes from the Feds (FEMA) and State Emergency Management, This subject was brought up, I don't remember if it was part of the course or just a question asked.
I was advised by people who shoud know: "Don't sell off your old electronic equipment or scrap it. Store some of it in sealed ammo cans, and put some of it back, The event of an EMP strike is not great, however the Sun is capible of doing just as much dammage at any time." At least at the time (5 years ago) I was told " Ammo cans will sheild electronic devices quite well as long as a cardboard or similar barrier is placed inside to keep the objects from contacting the top, sides or bottom of the can" I was also advised that a Gun Save with a carpeted interior should serve the same prupose. Hope this helps.