Delete All URL Rewrites In Magento
You may wish to delete all URL rewrites from URL Rewrite Management in Magento at some point, especially if you are frequently importing/exporting product and category data.
Simply run the below SQL query and all rewrites will be wiped.
SET FOREIGN_KEY_CHECKS = 0;
TRUNCATE TABLE `core_url_rewrite`;
SET FOREIGN_KEY_CHECKS = 1;