Years ago I bought used Front and rear Koni's
I have since bought new Bilsteins and I have no idea if these are worth re selling or sending them off to recycle the steel?
They do not leak and have shown no signs of abnormal wear.
since they have not seen any road use during my possesion I wonder what I can do to insure their condition?

If they're the vintage 70's - early-80's Konis, then they may be worthwhile cores for somebody wanting to have Koni restore/rebuild them for a CW car.

Koni does that service themselves, but not cheap.