How do I post a newspaper ad to declare I will not be responsible for bills incurred by others,do I need a lawyer for this?

Why would you have to post a newspaper ad in the first place?

If you don't co-sign the loan with them, what is the problem?

I never mentioned a loan. But during a separation one party can run medical bills and other bills up in your name. Would an ad in the paper declaring that your not responsible for any debts by other party stop them from charging you with the bills?

Hi,
I have missed something here, but in answer to your question now, YES, you need a lawyer. If you are going to be separated or divorced, you definitely need a lawyer. He/she can tell you what to put in a newspaper, and if you need to in the first place. Been there... done that.
I do wish you the best of luck.

A little more information please. Bills incurred from what? From who? Did you have a roommate? Were you married getting divorce? What?
Some more information would really help us to help you. Thanks.