Depends how they have been stored, Dusty. They are probably not viable but there is no harm in trying.
Fill a 3 or 4 inch pot with seed compost, sow the seed, cover with grit and keep in a cool shady place for a year or two.
You could also try planting a few seeds just below the surface in the place that you want them to grow.
If you throw them in the bin they certainly will not grow.

many thanks for that - I certainly wont put them in the dustbin!

I woulld try soaking them in water for 24 hours before planting them, to soften their seed coats.

Eryngiums, one of my favs - esp Alpinium, do not like being moved, so as Bulbaholic says plant the seeds in the place you want to grow them. They prefer full sun and will do best in it, but I have seen them grow well and to about 50-60 cm's in part of the garden that gets no direct sun. They do not need much watering after establishing themselves.

again, many thanks, I did grow (but not from seed) another Eryngium (Planum) but not so pretty and a bit untidy. A lot of our plants do quite well in gravel so I might try that if they ever come to anything!