The super separator trick

This is similar to Creating a Haas effect. Create an aux track with a short delay, below 4ms. Drop the gain about 3dB and start looking for a setting that either makes the part come out of the mix (or makes it sound worse, in which case, flip the polarity). Send the other part to the aux track and flip the send polarity to create equal and opposite comb filtering boosts and cuts.¹