Forensic technicians often need to obtain fingerprints from mummified, putrefied, or burnt bodies. However, it is not possible to ink eroded or burnt tegumentary surfaces to produce decadactylarian fingerprints. Therefore, forensic pathologists often use acetic acid for phalanx rehydration. Immersing the fingers in an ultrasonic container filled with a 20-percent acetic acid solution improves this method. The use of ultrasonic waves accelerates rehydration and provides both detachment of epidermis and cleaning of ridges and inter-ridges within hours. This method has produced excellent results despite the poor conservation status of samples. The next step planned by the authors’ laboratory will be to combine other chemical products with ultrasonic waves. Case example, photographs, and 5 references (Author abstract modified)