Ok, here is the process, and I
had a few questions about it:
With running water and a stiff nylon brush, scrub the entire surface free of "green fuzz", allow to dry.
Use a magnifying light and a
sharp needle to remove and open any obvious green spots
still visible. With care these will not be obvious later.
Pre-pare a bath of 5 parts baking soda [sodium bi-carbonate] to 8 parts washing soda [sodium carbonate]. You may go by
weight or simple dry measurement, i.e. tablespoons full. Store the mix in an air-tight container.
Is washing soda just regular old laundry detergent powder?Use de-mineralized or de-chlorinated water for better results.
Where can I get this?Mix 2 tablespoon of the soda mix to three cups of water; add coins and heat the mix to boiling, reduce heat for a minimum of 5 minutes. Set aside and soaking to continue for an extended period of time. This should be at least 24 to 36 hours, for thick coins like
sestertius allow at least 72 hours. After the initial soak, rinse with clean water and give the coin/s a light scrubbing.
Do I just put 3 cups of water, the mix, and the coin in a pan, boil it, then lower temp, keep stove on for 5 minutes, and then let it soak?Repeat step 5, twice more.
After the last soak and scrub, dry the coins, and soak in 100% isopropyl alcohol, for about 20 minutes. This will
help draw out more water from the coin
fabric. Dry thoroughly, and seal with a paste wax, well rubbed into the coin.
Do I have to wax the coin?It is recommended that all bronze coins be checked periodically, as I have found "clean" coins suddenly break out 2 years after purchase.
While this procedure should not effect a true green
patina. It will remove any artificial coloring or re-patination.
Finally, I am extremely worried about damaging the coin. Will this process damage my coin? It is extremely small and thin, and billon, will there be any damage to the silver?
Finally, can I cut down the soaking limit from 24 hours to 12 because of the coins size? And also repeat this step only once? paper thin and 15mm is an extremely small coin.
Help is appreciated.
Regards,
Levon