Sure, olive oil has a bit of acidity (or was it alkaline) in it.

But can copper coins tone in olive oil?

I presume there is no oxygen in olive oil since I see my cheese sitting in it for
a year without rotting
I wonder if there is any sulphur in it but only an analysis would show that
( Sulphur from burning oil or cool to make electricity mostly SO2 )

It's definitely acidic, that's why it removes encrustation found on ancients. And yes it will tone copper - it will also remove toning from copper or silver given enough time.

Everything you ever wanted to know about olive oil - HERE

I knew it

Thanks for the great link GDJMSP!

Now if I did ask this question, obviously something awful has happened to my copper coins, which I will take photos tomorrow.

This is the original coin that I took photos of a couple of years ago:




Now it has become this:




Sorry Tane!

YiKeS! Could the olive oil have removed crud leaving what you see now??

What I did was to clean the coin, and hence you can see a clean red at the background. This had however almost zero effect with verdigris and hence prompted me with the olive oil.

The overall result was, sure it did remove a fair amount of the verdigris but it might be because of the cleaned surfaces, which attracted the verdigris residue to be deposited back to the surfaces, even though the olive oil was fairly green. (could this be what the people who try to artificially tone do as well?)

What did you clean the coin with before using the olive oil?
That might be the culprit rather than the olive oil.

With those colors you could probably sell it for more than you paid in todays market.

I've never had a coin soaked in olive oil turn those kinds of colors. Maybe a little more red but nothing drastic.

AuldFartte, I made sure the nasty chemicals were dipped in acetone and rinsed with deionized water throughly unless there was some unusual chemical in either the acetone or the water.

Nevertheless I was intriguided over how a cross managed to form on that coin. Should I sell this coin as "OMG A GOD HAS APPEARED ON THIS COIN"?

The olive oil won't turn copper blue like that. There had to be some ammonia residue to react with the acid or a similar chemical compund to yield that result.

Untouched photo of olive oil after having three verdigris covered coins soaking in it for 3 months. It's a pretty shade of green!

The obverse of the Indian Head came out beautifully, the reverse is nasty.

Burks - that's what I got for the rest of my other coins! Perhaps the top layer's verdigris has been removed from the top layer, but the bottom layer 'absorbed' the verdigris since it's much heavier?

this sounds like something for the Myth Busters.......