I would taper for the first few days like twenty to ten to five. That's me I wouldnt go off twenty. Unless you feel strong enough to do so. I'm on day seven off a four year methadone started at 90mgs tapered to 3mgs. I would suggest tapering first but it's all up to the person and how strong you are. Sometimes tapering is worse then ct for others. It's all what you feel you can do. And you CAN do it.
I would say drink alot of filtered water, anything to clense your system. Stay away from fatty foods and stuff. How much are you coming off of?