Rod1 and PilotDAR; very very good points.
I love winter flying, but it needs to be treated with great respect, after the Birmingham crash our simulator instructors came up with a demo on what it would be like on the jets we fly and it was not fun.
On my own aircraft (PA32) I use a soft brush on all surfaces and fluid on anything that won't clear by brush. A phenomenon I have seen is light ice left around the cowling/cabin area which melted in the heat from the engine/cabin and then ran back as water to the tail to create clear ice.
I have seen the anti-balance tab on a PA34 ice up and cause a nose up pitch moment. Finally I once flew a PA28 into unforecast ice in a hold (during ATPL training) the aircraft took up the charactersitics of a shot duck and came down no matter what either me, or the instructor did.
Watch how a large commercial aircraft is de-iced sometime, the flying surfaces are cleared with hot fluid and as far as possible the whole fuselage is cleared as well. Ice weighs a lot and taking off at MTOW with a couple of mil on the fuselage would put you over weight, outside of flight envelope limits with all the possible ramifications.Ice changes the shape and weight of an aircraft and means that you are flying an unknown quantity, that is the field of test pilots and best left to the likes of PilotDAR.
FF