Best way to gather emails from potential offline clients?

I have Lead Net Pro, but i'm a little afraid of running into a spam trap, and also, it seems to scrape a lot of junk emails.

I've tried getting them manually from Manta, but it seems like hardly anyone is registered. I went through 100 listings, and only found 4 emails.

Anyone have a solid solution? I have everything else in place, just missing emails!

Looking for the same as well