I've used Muc off for years and find it really works. There are two sorts though, one is for off road muc and I guess is stronger. I use the road stuff, wash it off with gallons of cold water then spray with the muc-off protection stuff. The Bonneville is coming up to it's third winter and only had three bits of rust (Exhaust bolts, carb bolts, inside final tube of exhaust), so I'm well happy.
Andy