How to delete unwanted drum programs or keygroups?

I'm constantly loading up programs to try them out.
How do you properly delete all the programs you don't want?
Sometimes I hit purge and doesn't seem to delete anything.

As long as the programs are not assigned to any tracks, they should purge along with their samples.

Main Screen...Pencil icon on the Program Field, Then Hit Delete!

Yes, delete the program first, then purge. Purging doesn't remove programs from memory, only samples