Tips to remove encrustations from late roman bronze

[dmar]

Hello all,

I am new to cleaning coins and collecting in general so please forgive my ignorance.  I have been buying uncleaned roman bronzes online and cleaning then by soaking in distilled water, which i change daily combined with light brushing with a trimmed down toothbrush. In addition to this I use wooden toothpicks to remove additional encrustation.  I can't for the life of me 'improve' the circled coins in the picture and I was hoping you would be able to aid me with your experience. The red circled coin has a cement like encrustation coating the right side of the obverse which seems impossible to remove.  The black circled coin has a red 'rust' like coating which I can't seem to remove and finally the yellow circled coin has a bump circled by red 'rust'.

They were all found in the same field in suffolk if that makes a difference.

Thanks,

dmar

[SC]

I would say that most of these coins (nice ones by the way) are done.  The light soil remains on dark patina look nice.  I would leave the bumps unless they are blocking key details. A few, like the large one at top left, might have some bronze disease though hopefully it is just dormant pitting from the acidic British soil.

Shawn

[dmar]

Thanks for your reply! The coins are nearly in the state in which I bought them and I didn't know whether I would be able to take them any further.  Thanks for the warning regarding the possibility of bronze disease.  I have tried to read up on it as much as I can but as it seems to be a devil that has many guises it's hard to be confident in a diagnosis from my limited experience.  Anyway i'm rambling, thanks again for your input

[areich]

Some of them, like the top and bottom left coins can only get worse, not improve through cleaning. The top right coin is pretty much the only one that could use some cleaning.

[dmar]

Thanks for the advice. The top right coin has a cement like encrustation which seems impossible to remove. I was able to remove something similar on another coin but took away some of the patina with it so i'm reluctant to try it again with the tools/experience I have as the top right coin has quite an attractive reverse.

[Lee S]

Hi Dmar,

  Nice bunch of coins, especially for being UK finds!!!

   The way I would approach the top left coin is with a needle, bent 90­° about 1mm from the end, with which you can "flick" off very small flakes of the encrustation. Just be sure to always work away from the coin and you wont do it any damage.. if you find you are making no progress then try carefully applying a drop of lemon juice ONLY on the dirt, letting it soak for half an hour, wash off well and retry..

  Another useful ( and cheap!) tool I use is a c.12cm long length of stainless TIG welding rod, ( see photo ) sharpened to a point on one end , and a chisel blade on the other.. you will need to keep a sharpening stone with it, but the flat side is perfect for "shaving" away encrustations, and also those shiny calcite like deposits, ( Middle coin on the  left... I'm looking at you!!! )

  Can you post pics of the other side? for no other reason that I am curious !! ( I love UK found coins!! )

 Best wishes,

Lee.

( If you don't know any welders, and you live in Europe, send me a PM with your address and I'll knock a few up at work and send them you.... )

[dmar]

That's a picture of the reverse with the coins flipped in situ. I'll have a go with a needle today and see if I can make any headway. Thanks for the offer but i'm sure I can get one made up for me locally. On a side note Lee S, good job on the coins for round 16 'never ending cleaning comp' especially coin number 2

[areich]

Nice coins. I would take most of them out of the DW, dry carefully and thoroughly and call them done.