To delete stations on your Roku, open Pandora* and go to My Stations (or My Music sorted by Stations if you're a Pandora Premium subscriber).
Using your remote, move your cursor over the name of the station you'd like to delete and press the star button on your remote. This should display the option to delete the station (or remove it from My Music).
If you have an earlier model of Roku, you may need to delete those stations from our website or another device. (Your changes will carry over.) If you need help deleting stations from another device, please let me know.
*To ensure you open the main Pandora app (and not our voice-enabled lightweight app), open Pandora from the menu of your Roku, not via voice command.