I tried the Geo plugin in my 1.5 install, as I suspected GeoURL wasn’t finding me anymore. Turns out the plugin doesn’t work as expected and doesn’t come with instructions on how to clean up after it.
Took me a few searches of the WP support forum, and finally found something that worked. Go in your mysql database, change to the wp database, and use this:
delete from wp_postmeta where meta_key='_geo_location';
You can of course replace
_geo_location with anything you need to clean up. To see what your options are, try:
select * from wp_postmeta;