Driving/walking for dollars yellow letter advice needed!

Hey guys,

        Ive been doing a lot of walking for dollars in neighborhoods near mine and I have a lot of addresses that I would like to send letters to, but I have a couple of questions:

1.  Should I mail a letter or would it make sense to maybe tape something to their door or slip the letter striaght into thier mailbox?

2.  I have seen so many ways to word a driving/walking for dollars letter, but I would really like to hear from someone who has actually had success doing it and know what their letters actually said. 

As always, any help is appreciated!