I bought rolls of forever stamps for letters and postcards.

Auction.com and Xome.com are ok, as is Foreclosure.com, but compared to off-market, you are late to the party on all of these.There are several companies that provide off-market data like Rebo Gateway and List Source, but they really only work the most effectively when paired with a corresponding Yellow Letters (or similar) postcard of letter mailing because there are so many records.

@Eric Tillmon Postcards , or even yellow letters seem to work well for the wholesalers in my area.

As far as the persistence part, I'd send them a yellow-letter or postcard every 90 days or so, reminding them that they could call you at any moment and take the 'problem' off their hands.

Sending letters and post cards can be effective if you find the right mailing list.

Next month I will send mail to the same 700 people; though I might send postcards for the second round.

Mailer post cards are the best lead generator-  I send about 2500 mailers to each county monthly by going on the county website and downloading lists of land owners. 

I am starting a new Direct Mail Campaign.Based on the designs I have seen on vistaprint or any other website, there is no return address place on the large postcard.

Sending a single postcard or yellow letter would be pretty expensive but possible sure.

I received two postcards today from Julie Hicks imploring me to call her phone number in order to get to listen to a recorded message.