have descover by accident that if you mix tamiya epoxy putty with isopropilic alcoholl you can desolve it !. and it may work with greenstuff also.isopropilic alcohol you can find it at any drugstore at your neiborhood.
Kneadatite (like most putties) is pretty resistant to weaker solvents when set. You may see lifting of a feathered edge but overall it should have little effect.