How to sell online leads?

Hello everyone
I collected with my partner in last year dentist leads, some lawyer leads..etc
We built sites like, visitdentisthouston.com and we gathered people interested in those niches...we never completed this, and sites are now closed down because we started working on something else and we totally forgot about this..
My question is, can i contact owners of websites in my niches, and ask them if they want to buy leads from me?
And if they say yes, how do i show them they are real leads, how will they trust me etc?
I never sold this so if anyone more experience with this, please help.


Thanks for reading!

The problem with leads is either you keep them active or they go cold after a while. You need to sell them white hot, maybe even link them to a pay per call option as well. Also, keep in mind that the niches you are targeting are fucking packed with scammers and losers trying to make a quick buck, making conversions harder for you.

I've read a few people post about a method like this few years ago.
Basically print out your leads on a sheet of paper. Number them 1-5. Go in person to the business and say you have these hot leads for them you gathered. first few are free so they know it's legit. after they're satisfied, they can buy more off you for $x or on a monthly contract. mention you're going to their competitors with same thing to intice them to buy. you can even put businesses against each other to get the highest bidder.
you can go the extra mile and print the leads on your companies letterhead to make things more professional, amung many other things.

Thank you all for helping out...my main issue is i want to do this online, so we can only talk via email or maybe via phone, but my english is not native language so it is not professional at all...so when i send them for example so sample leads 2-3 mails...they will contact them and how will they know they are real? Maybe some of them are not interested anymore, or some of them will not reply at all? Because mostly we gathered emails not phone numbers etc..
Thanks

Email is typically a lot harder to get a reply out of vs call.
Call them up. Let them know what you have. Email them your leads (or give them over the phone) if they're interested in what you have.
If they turn into sales, they have no reason not to keep buy more from you as long as they turned a profit.