How to properly Clear a Queue containing structs?

I have declared a basic struct like this

private struct ValLine {
  public string val;
  public ulong linenum;
}

and declared a Queue like this

Queue<ValLine> check = new Queue<ValLine>();

Then in a using StreamReader setup where I'm reading through the lines of an input file using ReadLine in a while loop, among other things, I'm doing this to populate the Queue:

check.Enqueue(new ValLine { val = line, linenum = linenum });

("line" is a string containing the text of each line, "linenum" is just a counter that is initialized at 0 and is incremented each time through the loop.)

The purpose of the "check" Queue is that if a particular line meets some criteria, then I store that line in "check" along with the line number that it occurs on in the input file.

After I've finished reading through the input file, I use "check" for various things, but then when I'm finished using it I clear it out in the obvious manner:

check.Clear();

(Alternatively, in my final loop through "check" I could just use .Dequeue(), instead of foreach'ing it.)

But then I got to thinking - wait a minute, what about all those "new ValLine" I generated when populating the Queue in the first place??? Have I created a memory leak? I've pretty new to C#, so it's not coming clear to me how to deal with this - or even if it should be dealt with (perhaps .Clear() or .Dequeue() deals with the now obsoleted structs automatically?). I've spent over an hour with our dear friend Google, and just not finding any specific discussion of this kind of example in regard to the clearing of a collection of structs.

So... In C# do we need to deal with wiping out the individual structs before clearing the queue (or as we are dequeueing), or not? And if so, then what is the proper way to do this?

(Just in case it's relevant, I'm using .NET 4.5 in Visual Studio 2013.)

UPDATE: This is for future reference (you know, like if this page comes up in a Google search) in regard to proper coding. To make the struct immutable as per recommendation, this is what I've ended up with:

private struct ValLine {
  private readonly string _val;
  private readonly ulong _linenum;
  public string val { get { return _val; } }
  public ulong linenum { get { return _linenum; } }
  public ValLine(string x, ulong n) { _val = x; _linenum = n; }
}

Corresponding to that change, the queue population line is now this:

check.Enqueue(new ValLine(line,linenum));

Also, though not strictly necessary, I did get rid of my foreach on the queue (and the check.Clear();, and changed it to this

while (check.Count > 0) {
  ValLine ll = check.Dequeue();
  writer.WriteLine("[{0}] {1}", ll.linenum, ll.val);
}

so that the queue is emptied out as the information is output.

UPDATE 2: Okay, yes, I'm still a C# newbie (less than a year). I learn a lot from the Internet, but of course, I'm often looking at examples from more than a year ago. I have changed my struct so now it looks like this:

private struct ValLine {
  public string val { get; private set; }
  public ulong linenum { get; private set; }
  public ValLine(string x, ulong n): this()
    { this.val = x; this.linenum = n; }
}

Interestingly enough, I had actually tried exactly this off the top of my head before coming up with what's in the first update (above), but got a compile error (because I did not have the : this() with the constructor). Upon further suggestion, I checked further and found a recent example showing that : this() for making it work like I tried before, plugged that in, and - Wa La! - clean compile. I like the cleaner look of the code. What the private variables are called is irrelevant to me.