Poor processing of Kodachrome, particularly the re-exposure step, can result in murky color. Part of one layer gets the dye for a different layer, which mucks things up. The discount non-Kodak Kodachrome processors were very poor value. Kodachrome just loses dye density if you manage to fade it my excess exposure to light.

Ektachrome is the classic "goes pink" film. The Applied Science Fiction "Restoration of Color" feature (part of Nikon Scan) can do wonders, as can experienced work with the red, green, and blue curves. Ektachrome (of the fade pink generation) is very sensitive to heat, keep it cool and dry. Air conditioning helps a lot.