After serious thinking alan_m wrote :
Probably best to treat these tubes of glue as open, use immediately and
chuck the tube away.

That is what I do, they don't keep once opened. I tend to save up a few
items which need the attention of superglue and do them all together.

Note a mist of water sprayed on superglue, speeds up the setting. It
sets near instantly on fingers, due to the skin moisture.