Debate: Cleaning found coins with distilled water vs. leaving them dirty

I pulled a 1790s British halfpenny from a park in Philadelphia last weekend and scrubbed it with distilled water, but my buddy says I ruined the patina by cleaning it at all. Which side are you on - clean enough to see details or leave the dirt for value?

2 comments

2 Comments

troyp3710d ago

Honestly that 1790s halfpenny is a tough call. I pulled a 1770s King George II copper from a Maryland field last fall and did the distilled water soak for about 20 minutes with a soft toothbrush. The key is to not scrub hard, just let the water loosen the dirt and gently wipe the surface. If you scrubbed it like a dirty dish you probably took off some of the original surface, but if you were gentle the patina should be fine. Your buddy isn't wrong about value dropping if you scrub off the dark green or brown crust, but a light clean to see the date and bust is usually okay for coppers that common. I'd say next time try a longer soak with just water and see if the dirt falls off on its own before you touch it.

troy_owens9d ago

Yeah but 20 minutes in distilled water with a soft toothbrush might be overdoing it too. I've found that even a gentle brushing can pull up some of the lighter surface crust if the coin's been in the ground for two centuries. That 1770s King George you found probably lost a little of its original detail around the letters even if you didn't notice it. For coppers like that 1790s halfpenny, I'd say a quick dip in distilled water and just letting it air dry on a paper towel is safer than any brushing at all. The dirt that falls off naturally is the only stuff that should come off.