Forgotten but not gone

TEMPO SLICED GREEN BEANS says the lettering on the plastic pouch I picked up on the beach where we went to exercise the dog and the child. (I always try to pick up litter.)
VISIBLE VALUE 1/9
No, wait - whaaat???? One and nine?? One shilling and nine pence?  Is that British sterling pre-decimal currency? Which ceased to be used in 1971?

I took the pouch home to examine but there were no further clues and an internet search came up with no record of Tempo frozen veg past or present that might carry the numbers 1/9  in any other monetary form.

So I have to conclude that this item of plastic packaging has been lurking under sand or sea, weighed down by its cargo of grit, for over 50 years.

I am not the first or last to find such aged plastic litter. See here and here for example. What a legacy to leave for future generations. 
Will SHE be finding stuff we throw away today still around in 2071?