[development] uninstall: deleting all variables of a module

Hello List, I want to implement the uninstall hook for scheduler.module (D6). Removing the schema and configuration variables is pretty straight forward. But scheduler lets the user configure some values depending on node type. These variables are called 'scheduler_story' or 'scheduler_touch_event'. To remove these I would need to know all the node types that have ever been used at that site or I could enumerate everything in $conf that begins with 'scheduler_'. What is the recommened way of doing this. Is is even a good idea to access $conf directly? Thanks, Eric