g1smd - 11:50 am on Jul 16, 2010 (gmt 0)
Use a question mark on the redirect target to clear the query string.
The redirect also needs a preceding RewriteCond testing THE_REQUEST so that the redirect only fires for direct client requests, not as the result of a prior internal rewrite.
Theres several hundred prior examples of this code in this forum. It's a question that has been asked every week since the forum began.