freeing stainless swageless fittings

[Gmc28]

not moto related at all, but figured there are some minds in this group which may have a hot tip on this question i'm noodling:

Replaced the rather large deck at my place this summer, and was planning to re-use the stainless cable and fittings from the old deck.  Swageless fittings on each end of long runs of 5/32" stainless cable.  But can't get the swageless fittings un-done.  None of them.  

there's a little tight fitting stainless washer that goes around the cable, then the threaded fitting pushes/jams the cable into the opposite narrowing opening so it locks in place.  Unscrew the fitting, use various tools to try and release the cable from the now loose threaded fittings, but no luck. 

bought a little gizmo online that's supposed to go around the cable from the outside and allow me to push the lock washer back in the other direction to free it and the cable, but its just bends. 

Thikning i may soak them in penetrating oil and try again.  But thought maybe someone else has experience with such oddities as this and has ideas to share.  (pictures later if i get home this week)

cheers