To deactivate playlists:
(If you play on your computer) Go to the playlists section, by selecting the record with the plus in your SongPop navigation.
(If you play on a mobile device) Go to the “Shop” and select “Playlists”. You can also access this by going to "Profile" and "Owned Playlists".
Select a playlist that you own, but wish to deactivate. As you can see it will say "On" in the spot that usually tells you how much the playlist costs.
Here, slide the switch to Off.
You will receive a confirmation asking if you want to deactivate the playlist and it will charge you 100 coins.
The same will happen when/if you decide to reactivate the playlist.
Please be aware that deactivating a playlist will not prevent other SongPop users from challenging with this list, it will only remove it from your possible selections for challenging with.