VFHwebdev on "[Plugin: WP Super Cache] Plugin won't uninstall fully"

I wanted to try out WP-Super-Cache on my multi-site install, ran into some problems and am now having trouble fully uninstalling the plugin.
Disabling the plugin on all blogs didn't do it. There were still some caching issues with feeds and pages on some sites (many of which never had WP-Super-Cache activated on them).
After disabling it in all sites, I deleted the plugin via the wp-admin area.
Caching issues are gone but many of my sites are now displaying the following message embedded in the HTML of the public site.

WP Super Cache is installed but broken. The constant WPCACHEHOME must be set in the file wp-config.php and point at the WP Super Cache plugin directory.

Any suggestions of how to remove this and fully uninstall WP-Super-Cache?

http://wordpress.org/extend/plugins/wp-super-cache/