New investor in NYC looking for the best way to get contact info.

[Jonathan Carroll]

Hello Bigger pockets... I am a new investor in NYC looking to buy my first flip on my own. I have worked on a flip with another investor with a deal they brought to the table. Now I want to begin finding my own deals. I have lists of pre foreclosures and foreclosed properties but I do not have phone numbers. What are people using to acquire phone numbers? Any help would be greatly appreciated!