The phrase goes by "Negative Heart, Lock On! - Open Heart!".
Other techniques that may be used to cleanse X-Eggs/ X-Characters are:
- Seraphic Charm's "Angel Cradle"
- Amulet Clover's "Remake Honey"/"Remake Honey Special"
- Amulet Heart and Platinum Royale's "Platinum Heart"
- Yamato Maihime and Clown Drop's "Queen's Waltz"
Shugo Chara!! Doki-In season two of the anime, Amu learns to use a stronger version of Open Heart to cleanse Mystery Eggs and remove the Character Transformations of those corrupted by minor antagonist Lulu's ruby necklaces. She can also use it to purify X-Eggs and X-Characters.
Shugo Chara! Party
In episode 24 of season three, Amu, while in the form of Amulet Dia combines the power of Open Heart with that of Rikka Hiiragi, who is in the form of Pure Feeling, to cleanse and restore X-Eggs. The enhanced effect of this ability also restores broken X-Eggs.
- In the first Season when Amu purifies a mass of X-Characters at once they are never shown being purified, only a shot of Amu is used instead. This presumably due to the fact that Open Heart shows the X-Character's true form before it returns to its egg and most of the X-Characters there were never even shown.