To use a metal trash can for an EMP attack-Event- to keep your electronics safe, this is a must watch, you will see many others say things different, watch the DR's Test amazing. It works. He is using something I used in the audio business a spectrum analyzer a great one. He shows how the noise Db changes , wow see this.
You tube user words as follows;
EMP Trash Can Faraday Cage Testing in Lab
Published on Jan 2, 2014
Tests are conducted to measure how effective metal garbage cans are at blocking high-frequency energy, such as that released by an high-altitude nuclear electromagnetic pulse (EMP). Tips are provided on how to greatly improve the shielding effectiveness.