Gold and mercury form an amalgam, so you would still have had something that looks like a big hunk of metal. I suppose you wouldn't have known whose gold that was, but the fact that you had a large chunk of gold-mercury amalgam in the lab would have been not so good.

Edit: Looking at some videos, it appears you could get something that looks like regular mercury. I'm wondering how much mercury you would have needed to solubilize a medal. They may also not have had that much on hand, HCl and nitric acid are way easier to find.

> They may also not have had that much on hand, HCl and nitric acid are way easier to find.

At the same time, Mercury use was way more widespread than now in laboratories, so it may have been readily available as well. A number of things were banned or heavily restricted for laboratory use in relatively recent history (80s~90s).

> Gold and mercury form an amalgam

Sure, but if you have a sufficient amount of mercury, that amalgam will remain invisible to the eye as Mercury is not translucent - and you can just write "mercury" on the flash and you can be sure no-one will dare to touch it.

WWII-era soldiers may not have been as fearful of the fun that is mercury as we are today.

> you can just write "mercury" on the flash and you can be sure no-one will dare to touch it.

Remember we're talking about 1940. Whoever discovered it might very well take it off the shelf to play with it. ;)

Oh, Mercury poisoning has been known for a very, very long time, and certainly well documented since the late 1800s.

https://en.wikipedia.org/wiki/Mercury_poisoning

And yet my parents (both born in the 1960's) both played with beads of mercury on their desks in school on numerous occasions... It was pretty common

When I was at school (1980s) the teacher had us line up and put our fingers in a flask of mercury. It was a very peculiar sensation. I probably wouldn't want to repeat that "experiment" today.

Sure, I'm not saying the general knowledge of mercury poisoning was commonplace back then, but in the scientific community it was, I believe, well known already.

It was the Nazi soldier community they were worried about.

Mercury poisoning has been known for some time, however people in the general public knowing or caring about mercury poisoning is a pretty recent phenomenon.

I did not know you could dissolve gold in mercury, pretty cool. After a little research, I found out that the process can also be reversed (obviously, since it's used for gold extraction), like it was with aqua regia to recover the dissolved medals' gold, by simply evaporating the mercury (since it's boiling point is much lower than gold's):

http://en.wikipedia.org/wiki/Amalgam_(chemistry)#Gold_extrac...

http://nevada-outback-gems.com/Reference_pages/Amalgamation....

This however, has to be done in a controlled manner due to the toxicity of mercury, which is also why mercury apparently isn't commonly used to extract gold anymore.

> This however, has to be done in a controlled manner due to the toxicity of mercury, which is also why mercury apparently isn't commonly used to extract gold anymore.

Yes, because mercury vapors can directly transfer to your brain once inhaled and cause neurotoxic damage.

> why mercury apparently isn't commonly used to extract gold anymore.

I wouldn't be so sure about that. Out of sight out of mind. But maybe not out of your personal electronics.

Presumably a yellow liquid is far less conspicuous than a shiny metallic liquid, and both acids are commonly stocked. I think it's easy to forget that obtaining chemicals on short notice was not always easy (especially not in a country that's just been invaded).

You can also dissolve gold in lead, as my great-uncle discovered when he thought he'd hidden his money somewhere safe when a UK Nazi invasion seemed imminent during the second world war...