When the state of degradation of a coin makes its study and classification impossible, to such an extent that what we have in our hands is little more than a rusty plate, it is time for forensic numismatics. As in forensic medicine, the remains always provide, to a greater or lesser extent, information that can be very valuable for their identification. Last Sunday, at one of the many stalls that professional numismatists have historically assigned every Sunday of the year in Madrid's Plaza Mayor, I bought a piece that had seen much better times, and I only acquired it because of the challenge that was his classification. I have to say that from what was intuited on the obverse, I knew that it had to be 4 or 8 maravedís of Carlos III or Carlos IV, however I was much more inclined to it being Carlos III. With reference to the reverse, the information was null, due to the enormous quantity of clayey concretions that it accumulated. Therefore, regarding this piece, I had to confirm that it belonged to Carlos III and also find out, if possible, the mint, the year of minting and the face value. Below I attach the images of the state in which I bought it and how it turned out after a thorough cleaning with specific fiberglass punches for this purpose, and the application of microcrystalline wax to stabilize the piece and enhance the reliefs. Conclusions: These are 8 maravedís (this data was provided by the weight and diameter), from Carlos III, from the Segovia mint and minted in 1776. Finally, I am attaching a file photo of another identical coin, but in a magnificent state of preservation.