Gentle acids used to extract metal ions (IMAGE) KTH, Royal Institute of Technology Caption After an ultrasound bath, the samples soak in mild acid. Credit David Callahan/KTH Royal Institute of Technology Usage Restrictions Credit must be given to the creator. Only noncommercial uses of the work are permitted. No derivatives or adaptations of the work are permitted. License CC BY-NC-ND Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.