Yes, can lock down the clutch pedal. [Since I screwed up and let it sit with clutch engaged for two years, leading to this problem ...] NOW... I use the pin/spring thing on the pedal to disengage the clutch every night - or whenever the tractor is parked.Don't know if this would help or not, you can lock the clutch pedal down. Not sure if that might help pull the clutches apart or not.
Plus for last 2 days, I rock the tires every night (engine off - clutch locked down - in high gear - PTO engaged) to try and get the PTO secondary clutch to let go.
This worked to free the main clutch. Now hoping it works on the PTO clutch.