To save the shows recorded on your Tivo from imminent deletion.
The graphic icon used to indicate that a recorded show may be deleted to make room for new recordings features an exclamation point. Thus you save the recording by "de-exclamation-point"-ing the show.
The penultimate status of a show that may be deleted does not have the exclamation point, but instead a yellow dot. To extend the life of these shows is to "de-yellow."
I'll come to bed in a moment; first I have to dexclaim my shows.
I forgot to deyellow last night and I lost this week's episode.