I have to say this made me think… If granny is in her box how advisable is it to advertise it to the world?
Maybe the fisc will now be looking for their share of death duties due since, one presumes, it was not declared on her demise…
this sort of thing happens more often than one might think… like finding a car in the back of an old barn…
there will be correct ways of dealing with it… who knows who has something which was thought to be worthless, then turns out to be a picasso… (mmm must check out the old paintings in the attic…) 
and, if you want the money… you have to sell… and that has to be done correctly…
must confess, I shall be checking out the oddments we seem to have gathered over the years… although my siblings took what they perceived to be the best bits, every time… 
not sure how I would react if …
I don’t think it will worry us.
Nor us as the old ruins were completely demolished to make way for our new build bungalow en bois.
Still, there’s always the 2000 Mètre carré attached woodland which might harbour some secrets…
there’s a ruelle which has collapsed… right by our house… and I’ve made it clear that if buried treasure is found whilst doing the repairs… it’s mine… ('cos I found and reported the collapse) 
Potential treasures come in all shapes.
In the uk a resident in the Wirral unearthed an old poster in the loft. It was for a gig in a community hall in Heswall and had the Beatles on it along with other groups. I’d guess this was a 60s poster.
They put it to auction, auctioneer estimate £200 - it sold for £3,600
A friend in Scotland was recently de cluttering.
He unearthed a couple of pieces of Indian clothing which he’d inherited from a relative.
They’d an auction estimate of 50-100 and went for almost £20k. The auction was on line and some people realised they were a maharajahs !
I’m always amazed at seeing old rally plates (from 2000s) at brocantes - not competition ones but those for officials- going for anything from €5 to 20.
One of these days I’m going to have to look out all my real competition ones - metal ones from the 70s for the Monte, TAP, Tulip, London to Sydney etc - and make a fortune 