Hi Kooky, or whoever can help me with this :-)

I have moved all my games successfully from device 1 to device 2 by using login feature.
The problem is, now I have all my games (same storm ID) running on both devices.

I want to give device 1 to my sister and she wants to start playing the games from beginning (level 1) and I also don't want her messing around with my games as well.
So please let me know how to delete all my games from device 1 so my sister can play fresh from the start and make her own storm ID?

All devices are using iOs 7 if this info maybe useful?

Many thanks x