Specific preferences are courtesy of /u/pxji of Reddit.
1. Copy the following text:
user_pref("browser.pocket.api", "0.0.0.0");
user_pref("browser.pocket.site", "0.0.0.0");
user_pref("browser.pocket.enabled", false);
user_pref("browser.toolbarbuttons.introduced.pocket-button", false);