Use Fire Wheel 100 times and Team Rocket will disband.
In any case, assuming that the radio tower is still open, what are the final Rocket characters saying, if you have the appropriate items? They generally wouldn't stay around for long after battling. Other than that, if you can't go back before the Pryce battle, you might want to cede Goldenrod City to Team Rocket, and proceed to Blackthorn if possible past the non-player character who would be in the way. TR in Goldenrod doesn't give you a badge, per se. There may be another way, such as tempting them to fight with a Pikachu? I believe the final TR grunt might not be a specific character in battle, so that might not help in isolation. Anyway, a bit of an interesting outcome, a bit CYOA. There might be some other options you may wish to try.