How to fix sealed new yellowed IMEX decals?

[Dpate]

So i have this kit IMEX Harley Davidson FLSTF Fat Boy Model 1/12 and the decals are brand new but they are yellowed.  I've heard of methods like putting them in a zip lock bag and putting them in the window for the sun to fix the yellowing and than apply micro scale decal film.  I've also heard using a UV lamp can fix the yellowing because the UV rays from the sun is what fixes the issue.  I've searched everywhere and can not find any decals for a 1/12 Harley fatboy either.

[peteski]

I have bleached yellowed clear film on old Revell Can-Do wrecker decal set by placing them in a plastic bag and hanging them in a window to get exposed to sunlight.  That was years ago.  I don't remember how long it took, but I think it was couple of weeks (in the summer, northeast USA).  The yellow didn't totally clear up, but it enough to make the decal usable.

Of course I can't guarantee that it will work for you.