Deleting Old Sales Orders

We have hundreds, if not thousands of old quotes that had an expiration date of 12/31/5999.  I would like to start deleting these, but don't want to have to go one by one.  I tried a few of the utilities in a test account, but I'm not having any luck removing / deleting quotes from 1999 - 2009.

What is the best way to delete these old open quotes that are not expired due to the the 12/31/5999 date that was chosen when the software was set up.