If you develop a desktop based application, you’ll notice that the working set size is quite big. For an empty windows form application, the size can be around 20 MB.

While this is not a problem, sometimes you may want to ‘trick’ the user that your running application has low memory consumption. By using P/Invoke this is possible.

[DllImport("psapi.dll")]
static extern int EmptyWorkingSet(IntPtr hwProc);

static void ClearMemory()
{
	  try
      {
            EmptyWorkingSet(Process.GetCurrentProcess().Handle);
      }
      catch
      {
      }
}

I got this information from this article. You need to remember that this method will only affect the working set, not the private bytes.