I am back with my report of the experiment, undoing decal fog! The result? Well, I think it could be done, but my technique leaves something to be desired. ( Also am not the best photographer for this close up work at this point. )
As I had said, I did not try this on the model itself, but tried to recreate the problem on an extra piece. The problem was ending up with decal fog or silvery look under the clear edges beause of having put the decals down on a flat finish surface.
So, here is the recreated problem; Oh no, what have I done! Look at those decals! ( ignore the fingerprint and scratch, that has nothing to do with this test! )

I know! Someone on the FSM forum suggested getting Future to seep in under the decal. Ok, first I’ll cut a couple slits:

Now I will brush on Future, try to work it into the slits and brush around to try to get it to spread around underneath:


Finally I will recoat with flat clear, and the results are:

So, do we see a difference between the before and after? I guess not. It seemed that some future did get in under the decal, but I could not get it out to the edges. Maybe slits would need to be cut on each edge where the problem actually is; plus a smaller slit, fresh blade, so as not to leave the scar I did.
Somebody said they have done this successfully and I believe it. I just did not get it quite right. So I hope this was at least entertaining if not helpful.
In answer to my post here someone also suggested removing the decals, doing the Future coat, and getting after market decals to replace. If I were to fix this on my model I would do that. After all my wining about this however I am going to leave it, call this project done and move on.
Thanks again all for the input!