Any way to destroy internal classes that were instantiated?

I'm building a script that will instantiate some internal script when called. As in,

 public class Example : MonoBehaviour
 {
    private List<NewClass> newClassList = new List<NewClass>();
   
    public void MakeNewClass()
    {
       newClassList.Add(new SomeClass());
    }

    public void Activate()
    {
       foreach (NewClass class in newClassList) { class.DoSomething(); }
    }
 }
   
 internal class SomeClass : NewClass
 {
    // does something
 }

Now, this function worked just fine... but the thing is, I worry that that would be best practice to do so.

I am creating new class every time NewClass is created via new SomeClass(), but I never get to unload? or destroy? them. Whatever the correct term for that is. I am creating more and more classes without ever removing them, so I worry that this might cause some issue in the future.

Is there anyway I can destroy internal classes? I can't seem to find a way to do that.