Nothing to do with MD'ing or 
I bought these Roman Coins off of Ebay about 5 years ago, I think I paid about $15.00-$20.00 with shipping from the UK. I tried to clean then by hand a few times with non-abrasive/destructive methods and couldn't get much out of them. The web sites say not to get aggressive with them, no wire brushes, chemicals, electrolysis, etc... So I put them in the Drawer of Incredible Junk until the other day when I ran across them. I looked at them for a while then I wandered out to the workshop for few a beers and some power tool adventures. I looked around at what I had so I took one over to the wire wheel... didn't do much, stuck it in the electrolysis bowl and fired the power supply up... didn't do much. So what to do, what to do, ah, it dawned on me and I tossed the whole lot off them into the rock tumbler. I figured if I was going to mess something up I might as well do do it slowly. I let it run with aquarium gravel and dish detergent for about 2 hours, took them out and some looked like silver maybe, threw them back in for 12 hours and dumped and rinsed them. See the pictures below, I guess they are scratched now but the museum hasn't called and offered to buy them so I guess I am safe, I didn't destroy some great antiquities after all.
[attachment 93645 roman-2.JPG]
This is just the good stuff, lots of fragments and unidentifiable lumps.
[attachment 93646 roman-3.JPG]
[attachment 93647 roman-4.JPG]
[attachment 93648 roman-5.JPG]
I think this one below might be silver.
[attachment 93649 roman-6.JPG]
[attachment 93651 roman-8.JPG]
Checked Ebay, a packet of dirty coins like this goes for $50.00 to $80.00 now, wish I had bought more.
I bought these Roman Coins off of Ebay about 5 years ago, I think I paid about $15.00-$20.00 with shipping from the UK. I tried to clean then by hand a few times with non-abrasive/destructive methods and couldn't get much out of them. The web sites say not to get aggressive with them, no wire brushes, chemicals, electrolysis, etc... So I put them in the Drawer of Incredible Junk until the other day when I ran across them. I looked at them for a while then I wandered out to the workshop for few a beers and some power tool adventures. I looked around at what I had so I took one over to the wire wheel... didn't do much, stuck it in the electrolysis bowl and fired the power supply up... didn't do much. So what to do, what to do, ah, it dawned on me and I tossed the whole lot off them into the rock tumbler. I figured if I was going to mess something up I might as well do do it slowly. I let it run with aquarium gravel and dish detergent for about 2 hours, took them out and some looked like silver maybe, threw them back in for 12 hours and dumped and rinsed them. See the pictures below, I guess they are scratched now but the museum hasn't called and offered to buy them so I guess I am safe, I didn't destroy some great antiquities after all.
[attachment 93645 roman-2.JPG]
This is just the good stuff, lots of fragments and unidentifiable lumps.
[attachment 93646 roman-3.JPG]
[attachment 93647 roman-4.JPG]
[attachment 93648 roman-5.JPG]
I think this one below might be silver.
[attachment 93649 roman-6.JPG]
[attachment 93651 roman-8.JPG]
Checked Ebay, a packet of dirty coins like this goes for $50.00 to $80.00 now, wish I had bought more.