just say hi, dont worry im not gas and electric, phone etc, just been told that you and your neighbours were looking for a friendly, reliable, and good looking window cleaner haha...... bet no one is nasty if you are genuine..
I used to be a door to door canvasser, ive knocked so call no call zones and never been turned away on account of a door sign....just be confident and genuine, butter people up they just wanna feel special if you can do that they would buy a broken tele from you - anything!!
Good luck