Just make sure that the township, etc. that you are soliciting in does not require a permit to do so. There are many places that require a permit to go door to door. Many will not say anything if you are just hanging a door hanger, but may enforce it if you are actually knocking on doors. In fact, in may places there are even restrictions on when you may go to a door. example: between 9a and 5p monday thru friday.
Some do some don't. It is different every where you go.