Easy money

Went to the bank today to deposit some cash for a member.
Got chatting to the lady at the teller, and she asked what it was for as the lady before me just deposited money for silver.
My response was gold nugget.
She said someone just came in with 3x $200 Prince Charles and Lady Di commemorative wedding coins.
The bank can only exchange them for currency value. and sell them for currency value.
Got the 3 for $600, and one has gotta be worth that alone.
Even melted down they are 10 grams of 22k.
And if you take em to the fish and chip shop they are still worth $200 as legal tender...
Sounds like a no risk investment to me.
Time to ring all the local banks i think..
Anyone else struck this before????..
Found some online for sale at $700 and bullion price at $470 if melted..

Who needs a detector when you can do deals like that.
Chris