Prospecting Previous Business Contacts Without Ruining Relationships?

I am looking for some tips on how to prospect people I already know through a previous job I had. I have lots of phone numbers in my cell phone of people I called on as a non-profit fundraiser before coming to work in the securities industry.   It seems like there is a fine line there when it comes to not ruining a good relationship or engaging them in what I am doing now in order to help them. Some of these people I know really well, and others I am an acquaintance but there is a mutual respect. How do I call and let them know I really do want to speak with them without it totally coming off as "I'm calling because I know you have money and I want your business"?   This is something I've pondered for quite some time. Any help is appreciated. Thanks.