I have heard about using stretches sprue to replace sanded off panel lines, but never tried it. I've also read that you can just cut a new one in with a sharp #11, it'll leave a raised ridge on either side of the cut, that looks like a raised panel line. I think the best bet though, is to use acetone nail polish remover and a q-tip, that way you don't have to sand anything off. I wish I'd known about that technique when I'd started my F-18, I've lost lots of detail on the surface (and it wasn't great to start with)from sanding. The model isn't nearly as good as I'd hoped it would be, but I've learned and improved, so I can build something nice before too long I hope.
If you're just testing, try every method you can on a different part of the model and see which you like best. Let us know how it comes out.
madda
Madda
Trifles make perfection, but perfection is no trifle. -- Leonardo Da Vinci
Tact is for those who lack the wit for sarcasm.--maddafinga