FORVM`s Classical Numismatics Discussion Board

Numismatic and History Discussions => Uncleaned Ancient Coin Discussion => Topic started by: the10thlegion on June 29, 2019, 07:29:07 am

Title: cleaning process of a sestertius
Post by: the10thlegion on June 29, 2019, 07:29:07 am
About 4 months ago 3 dozen coins began the cleaning process. Something like this is new to me so may have done something wrong along the way (or could have done better). They started out soaking them all in distilled water for 3 months, changing the water twice a week. Then a soft toothbrush removed any loosened dirt. They cleaned up better than expected but could use more work. After that all were placed in olive oil. After 1 week there they faced the toothbrush again before being returned to a new oil bath. That is with the exception of 2 which paid a visit to H2O2 - which can be discussed in a different post when those are finished.

This is the coin I'm most pleased with the process, a yet to be attributed sestertius. Before the process one could, with some imagination and good light, just make out the outlines on both sides. Unlike the other coins this one didn't have a lot of dirt to remove so there is not much difference (at least to my aging eyes) after those 3 months. But I am really impressed with the results from the olive oil. Sadly before these came into my possession it appears as if someone tortured this coin with an ice pick - thus the multitude of white dots speckled across the surface.

The olive oil did wonders as one can now more easily make out the details of this coin. There are still a couple rough spots.

Kind of a side track semi related thought here --- The couple soaking in H2O2 are still soaking. It's a 3% solution and I change it out a couple times a day (when bubbles seem to slow down). What I read before using the H2O2 was to use 35% solution. I couldn't find it anywhere, well not exactly true - Granger sells a 500 ml bottle for $80 but one needs a business account with them and they only "deliver" to a business address, a little pricey for a nearly culled coin - if all else fails may try this route but for now a less expensive path of least resistance. Amazon has several for sale that were described as 35% diluted to 12% - why even begin stating 35% the concentration - who cares about the starting concentration. Further reading I learned the government regulates the shipment of H2O2 and anything above 12% cannot legally be mailed - probably why Granger only delivers to a business address. That said I did find someone claiming to sell 35% at a reasonable price (but have my doubts it's going to be like what I found on amazon) It has yet to arrive but when it does those 2 coins still soaking will experience the higher concentration of H2O2 be it 35% or 12%.

Back to this coin, should I call it good or should I do something else to it? distilled water? olive oil? H2O2? or something else?

The attribution process will begin soon too - any suggestions as to where to look? Augustus? Commodus?

Thanks for your interest.

Title: Re: cleaning process of a sestertius
Post by: B-Chicago on August 01, 2019, 09:21:26 pm
my recs

- ditch the olive oil all together and dont look back

- changing the distilled water twice a week is pointless, I change it about once a month or up to 10 weeks. if there's any funk in the water or an oily substance floating on top you know it's time to a) rinse & dry coins b) thoroughly clean container c) change water. in between a and b you may do x y or z but again, see above.  I use white vinegar to clean the containers. I might use it on silver coins (rarely) but never with copper or bronze.

- I have tried h202 and am convinced that route doesn't work for me. wont be going back. its also expensive

- some coins take several years to respond - patience is key

- rubbing alcohol might help get rid of the olive oil residue

- coin likely has cavities - look at the C on reverse

- also may have been harshly brushed with a ? grill cleaner ?

Title: Re: cleaning process of a sestertius
Post by: Chris F2 on November 17, 2019, 05:32:44 pm
And I would echo the "ditch olive oil" advice 100%. That method works well for some coins, but leaves others with a tough, greasy/smeary, intractible surface deposit that wouldn't have occurred using the distilled water least after in cases of a very long time OO immersion.

I started the hobby with lots of uncleaned late Roman bronzes back in 2004-2006ish w/Ebay stuff. Olive oil soaks was the standard recommendation then, and I maybe got 10% of my purchases identifiable with short (1-2 weeks) OO soak/scrubbing cycles. The I dropped the hobby for a bit, but left a few hundred LRBs soaking in OO for a decade+. Got back into the hobby last year, purchasing higher-end uncleaned coins and going the distilled water route.

Full agreement that most uncleaned Romans on the market need an extended DW soak. Soak them a bit with DW in a bowl and scrub them w/a toothbrush x 2 on day 1, then let them soak in DW for a couple weeks. Then rinse and pull out the clean coins. Repeat. Then let the remainders soak in fresh DW for a month. Repeat, extending the intervals to 2-3 months for each iteration. Patience is key here.

That DW path -- in my experience -- tends to land you with gradually more -- and a higher % of -- identifiable coins. With the decade-long soak in OO, I got a tiny few damn fine coins that responded really well to that treatment. Those that didn't, however, seem to have the greasy/smeary stuff that responds not well to other treatment, and is difficult to address w/o damaging the underlying coin. And I feel I'd have a much better coin in hand if I'd done the DW method, and it would have happened much faster.