So...in to soak. I used a tupperwear type container so I could seal it and shake the coins. After a couple of weeks, changing the water and brushing them, I decided to get more aggressive with one. This is the one I picked: Started soaking it in KOH (could have used NaOH, but had KOH), rinsing and brushing, then working with a dental pick and ended up with: In order to see the legends better, I photographed it against a black background with stronger lighting: Maximianus, Sacra Moneta Reverse, Ticinium mint, RIC VI 45 A or B I think, 25 mm, 8.09 g...corrections welcome. The rest of the coins also got the KOH treatment, but nothing this good. I'll be asking questions about some of them.