Deleting a mention isn’t an overly complicated task. To do this, hit the Remove button in the right bottom corner of a mention:
NB: When you remove a mention from the feed, the notification pops up with the Restore button in the left bottom corner, so you can restore the mention until this notification disappears:
But after it's gone, you won’t be able to restore this mention anymore.
Now let’s get down to deleting mentions in bulk.
First, enter the selection mode by clicking the user picture of a mention, choose the mentions you don’t need anymore, hit the Remove button and click Delete in the dialogue box:
If you want to select all mentions in the feed or in a particular folder, just hit the Select all button. And again, the Remove button and Delete in the dialogue box:
That's it for now!