The "gold standard" in pro studios is oeksound Smoothe. It's not cheap, but it's excellent for individual tracks (it's a great way to get rid of amp sim "fizz") as well as stereo buses and mixes. Waves Crurve Equator is very good and costs less. Both have free trials.
However, a sharp, narrow EQ notch between 2 kHz and 8 kHz may be all you really need. When you're dealing with that narrow a notch, it can be hard to locate the correct frequency and dial in the right amount of notch, but give it a try. I use this technique on many of my masters. It's minimally invasive and doesn't cause artifacts. If you need more info on this technique, I can post an excerpt from my Fender Studio Pro tips book.