To clear all querystrings, you can invoke the Request.QueryString.Clear();
which will remove all the querystrings at the url
To remove a specific querystring invoke Request.QueryString.Remove("name of the querystring"),
example:
http:
Request.QueryString.Remove("id");
or you can use
Request.QueryString.Clear();
which will remove or the querystrings
example
http:
Request.QueryString.Clear();
result
Url without the two querystrings (id,date);