UHNW Prospects - looking for advice

I have been reading these boards for three years but have not contributed until now. I have been in the business for a few years and I have built a solid foundation for my business. I'm no superstar but I am not at the bottom of the class either. Every single account I have opened has been from a cold call. I hunt rollovers. Well here's the reason for my post. Over the years I have come across the names of about 20 people who I know have 10-15 million bucks each with different firms. I have no connection to these people and no possibility for a warm introduction. I just know who they are and I have their address and phone number. 

Somy question is this, does anyone have any experience going after these types of people cold? Any tips or strategy would've really appreciated. 

I currently have about 200 account at an average of roughly 150k. So Mabey I'm wrong buti suspect I will need a different approach than the one I run like clock work on my current targets. 

Dont get me wrong I know what works for me and I'm not really planning on changing but it would be nice to pick up a whale or two.