What do you do with the returned postcards?

[Mark Redmann]

I have a few returned postcards from my direct mail campaign in Philadelphia.  They were returned saying the address I mailed to is vacant.  I was mailing to absentee owners (I'm not mailing to the house they own, but rather their primary residence)

What do you guys do with those? I have gone through some of them on the philly property owner/tax records website and found that they owe thousands in back taxes. What would be your next move on these? To clarify, I was looking up the address on the postcard (absentee owner primary residence), NOT the subject property address. The primary residence addresses are the ones that showed the back taxes.  What should my next correspondence be, since they never even received the postcard in the first place and do not know I exist? a simple note saying i want to buy your house?  what about a letter saying how I can help them, and explicitly saying what they will get out of doing business with me?

I saved all them thinking I should be able to convert these into a lead somehow.  Thanks!