Eighty years ago this month, the March 1942 issue of Popular Science carried a number of pointers on preparing for wartime blackouts. The magazine first noted that deciding whether or not to participate wasn’t a merely personal decision: If you didn’t follow the blackout instructions, then both you and your neighbors would be put at risk.

The good news was that it was very unlikely that large sections of the country would be subject to blackout. Therefore, it advised against running out and buying the necessary materials: You might wind up with a bunch of stuff that you don’t need, and even worse, you could cause shortages in areas where they were needed. So the key advice was to wait for official advice from civil defense authorities, and follow their instructions. In the meantime, you could read up to be prepared for that time, such as with the hints shown above. In addition, the magazine contained numerous ideas for blacking out various kinds of windows and doors. One key piece of advice was to remove bulbs from unused sockets, especially outdoors. No matter how well you were blacked out, an accidentally flipped light switch could make it all for naught for you and your neighbors.

When civil defense authorities gave you the instructions to prepare for blackout, you would be ready.