James,
In a nutshell, heat a bolt head to almost red hot and place it on the coin to transfer heat from bolt to coin.
Set a stick of hot melt glue on the coin and let it cool and adhere to the coin for 15 to 20 minutes and then give the stick a tug and the coin will pop out attached to the glue stick.
Heat the coin to separate it from the glue stick.
Doc started a thread discussing this technique but I couldnt find it either.
Be careful to keep hot glue off of wood surrounding the coin to prevent lifting wood when you pull the coin out.
Trap