Does {Ratchet Bomb} work for destroying emblems? Planeswalker emblems?
Emblems currently have no way of being destroyed.
Can't you just use {Planar Cleansing} to wipe everything or is an emblem not a permanent ?
You're correct, emblems are not permanents. They do not exist on the field in any manner.
For reference
113.5. (http://imtgapp.com/forum/index.php?action=imtg;area=rule;number=113.5.): An emblem is neither a card nor a permanent. Emblem isn't a card type.
Do you have a reference for that statement?
It's true.
113.2. (http://imtgapp.com/forum/index.php?action=imtg;area=rule;number=113.2.): An effect that creates an emblem is written "[Player] gets an emblem with [ability]." This means that [player] puts an emblem with [ability] into the command zone. The emblem is both owned and controlled by that player.
113.4. (http://imtgapp.com/forum/index.php?action=imtg;area=rule;number=113.4.): Abilities of emblems function in the command zone.
That IS strange..