I got this coin which was completely encrusted in minerals and oxides. Just awful. After hours upon hours in lye, vinegar, lemon juice, and every other corrosive substance I could find, it gave me nothing. So, at wit's end, I took it to the buffing wheel, and the results are lustrously lackluster. This proves that sometimes, your best effort just isn't good enough. Sort of looks like a dupondius of Nero, but the text I believe is ---VSCAES---- on the obverse, do not Nero. Maybe a Flavian? Might even be Germanicus. Who knows. Reverse is tentatively a wreathed S-C. Please post pics of your biggest failures.
My thought as well. I think I can just make out: .... VS CAESAR TI AUG around the portrait. One of my biggest failures is ID-ing other people's coins.