Anybody use Zip Letters?

[Frank Hinck]

I’ve heard of wholesalers & marketers using Zip Letters, the kind where you rip off the sides and top, looks like a corporate check or official govt notice (I know I generally open this type of mail). Thoughts if you’ve actually used this:

-when in your marketing cycle (pre/post yellow letter/postcard)?

-effectiveness % / response rate?

Do you then send them to a prerecorded number or Google number?