Yes you can delete tp's. and the blind scan will pick them up if they are active when you re-scan, however if you have a favorite that is not active 24hrs a day you should record the information and either manually enter or scan when you know it is active. When I re-scan a satellite I delete all tp's. and start with a clean slate. As far as deletion of tp's that are unusable, I did that when I first got my DBS3500 as I didn't know if there were any issues with overloading tp's with heavy blind scan usage. I still do not know if there are problems with overloading, but I have never had any problems.