And that means both normal mentions for The Blacklist, as well as any hashtags with those words in it, are stricken from the record for as long as you want.
Once that’s done, your feed will be free from mentions of Designated Survivor and The Blacklist or whatever else you want to hide your mind from.
According to Twitter itself, the default setting is “Forever,” so don’t go forgetting about what you added in there, in case you want to talk about it later.
In order to hush the loudmouths who cannot stop talking about who got eliminated from The Voice before you even watched the first battle rounds, all you have to do is add any particular words, phrases or names to a list of things to mute.