I want to empty a list. How to do that?
To give an alternative answer (Who needs 5 equal answers?):
list.Add(5);
// list contains at least one element now
list = new List();
// list in "list" is empty now
Keep in mind that all other references to the old list have not been cleared (depending on the situation, this might be what you want). Also, in terms of performance, it is usually a bit slower.