Have you targeting properties with Tax Liens/Delinquent Taxes? If so what marketing piece have you used?

[Tarique Jawed]

I'm a rehabber looking to send out direct mail to properties with tax liens on them because I think owing back taxes may be a reason some people want to sell.  Have any of you tried going after delinquent tax lists in the past?  What kind of marketing material (yellow letter, postcard, etc) has worked, and should it be specifically catered to those owing taxes?

I appreciate any feedback, thanks!