No need to rush and permanently delete them, but it’s a good idea to mark them somehow. Fresh impression is the most reasonable, so if the engineer of mixing and mastering services online immediately feels that something interferes with the main part, it’s best to listen to the track without this particular element or part. And still, how to stay as objective as possible while removing redundancies?
Firstly, priority is always given to the lead. Ask yourself if there are any parts that distract attention from the lead and “take over” the track? The examples of such elements include overly sophisticated pads (especially with sweepers), melodious rhythm parts or beautiful but inappropriate arpeggiators. All of those can be a real pain in the neck for an engineer. Nothing should prevent the lead from getting the main dramatic line across to the listener. However, don’t confuse interfering parts with counterpoints. They aren’t simply good, they are necessary; otherwise, the arrangement will sound poorly.
A counterpoint is a music part, which is parallel to the main one, as it disagrees with the main part both in rhythmic and melodic domains. It’s even better if the counterpart and the main part have a different timbre and tessitura.
Secondly, notice the parts that rhythmically conceal each other. You will probably need to give up one of them or thin it out during mixing. The second option is more difficult, but still possible.
You may also be interested to hear our examples of audio mixing mastering work.