How to loosen green encrusted sand on bronze?

RobertM

Junior Member
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Feb 6, 2019
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38
This stuff seems like it has actually grown on the coin. It is beach sand and corrosion all glued together and probably harder than the old Chinese coin.
How to loosen it up?
 

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This stuff seems like it has actually grown on the coin. It is beach sand and corrosion all glued together and probably harder than the old Chinese coin.
How to loosen it up?

If you just want to see what's left of it you can start by soaking it in cheap olive oil..the good virgin olive is less acidic..that can take a while..when the oil turns green you can wash it off with Dawn soap and put it in Zep purple industrial degreaser..that will loosen it even more ..then scrub it with baking soda..repeat as necessary..or go to CLR.. wash off and scrub again..lots of different ways..you can use lemon juice with salt and vinegar..but don't blame me if it gets eaten up.. electrolysis will work too..lots of ways if you are in a hurry and don't care about damaging it..chemicals are hazardous..use in well ventilated areas or get a respirator with chemical cartridges..
 
Some of the old "Cash" coins are valuable but...go slowly. Try olive oil first (neutral pH) as it is a solvent and will remove dirt and grime. Next you might try acids like lemon juice ( pH 2) or white vinegar (pH 2.4 @ 5%) or coffee (pH 5) and these will remove any shells and incrustation. [I just removed shell and sand encrustation from the top of a 2 1/4" silver topped alligator tooth by soaking the top only in white vinegar overnight and it came out great.] Finally, if all else fails, try hydrochloric acid (pH 0), also known as Muriatic acid, for a few seconds at a time, wash-off with water and check results, repeat. FYI Handle HCL with extreme care, goggles, rubber gloves, etc.
 
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