I have just found a biscuit tin of packets of Burpee Seeds from the US — swiss chard seed tape, carnations, heliotrope, geraniums, lettuces, basil etc. — about 30-35 packets dated from 1997! Is it worth my time to try to germinate them or shall I just dump them? It breaks my heart to do so but if it’s a useless exercise, I won’t bother. The tin was in the back of an upper shelf in a kitchen cupboard, completely forgotten about!
Some of these might well be still viable, but perhaps not.
Set up a test with a plastic tray and some tissue dampened. Sow a tiny pinch of each kind and number them. You can easily get 20 or 30 kinds onto an aveerage tray. Cover with plastic to keep moist and keep in a window sill indoors out of direct sunshine. Those still alive will soon show signs.