After spending two hours carefully scraping frost between the rivet lines on a C172 wing, I still had an exciting low level tour of the ravine conveniently situated at the end of the runway until I got to a speed that would give me a climb
After that it's been windshield washer fluid and squeegee until the wings shine.
That said some a/c such as the A310 are certified for take off with frost over the wing tanks, which can happen if you land with cold soaked fuel. Canadian regulations require perfectly clean wings in any case.