To be eligible your child must be 18 years old or 5 years must have passed from the last arrest or discharge from probation.
You must show you have been rehabilitated. In other words, your child has neither had any recent contact with the police nor participated in any further criminal activity.
Due to recent changes in the law, certain offenses are no longer sealable. The court shall not order the person's records sealed in any case in which the person has been found by the juvenile court to have committed an offense listed in subdivision (b) of Section 707 when he or she had attained 14 years of age or older.