Disclosure of removed or illegible identification marks occurs when the need arises to establish the origin of the object or to attempt to alter the original designation. In order to make it difficult to identify the subject, the offender removes all the marks characterizing the subject while applying the new mark. In addition to the most primitive character removal methods, there are those that make it difficult to evaluate the removal of the original sign. The publication presents selected methods of destructive and non-destructive testing which are used in forensic vehicle identification. The results of research on the detection of forgeries of vehicle identification numbers obtained using the methods discussed are presented in the publication. The presented results illustrate how easy it is to disclose attempts to process car numbers. As a result of the performed tests, the forgeries of the VIN (Vehicle Identification Number) were revealed by the chemical method in the Hyundai Tucson car and the magnetic method in the Nissan car. In addition, using the thermal method, a forgery of the engine number of the Daewoo Matiz car was revealed. In turn, in the Audi A6 car, an attempt was made to counterfeit the VIN using the permanent magnetic method, and the method of replicas was disclosed.