I sold a place middle-end of May and 3 weeks later, I got the tax notice in the mail.

You can also upload the documents there (not over e-mail as you were saying).

I plan to do primarily direct mail to the owners but wasn't sure if there are any other better ways. 

Recently in the mail I received a letter from a mortgage company telling me i could get $48k and bring my mortgage payment down from $3600 to $3000.

I tried doing direct mail myself, but the response rate has been very low.

Their rates are extremely high for new investors compared to other hard money lenders, and they include a lot of junk fees. 

Quote from @Donna Morelli: Hi I’m interested in a vacant property and know I can look up the name on tax records but won’t necessarily be where I can contact the property owners.thanks in advance. tax records should have a mailing address for the homeowner.

Does anyone have experience with direct mail marketing as both a Realtor and Investor? 

The response might be, 'One check with both names,' or, 'Two checks split 50/50, mailed to separate addresses' or something similar. 

This bit me a few months later when I sent direct mail and handwritten letters to homeowners as a wholesaler.