How do I paint over an exsisting popcorn ceiling? The original ceiling has stains and is dark and dingy.

You can just get some white ceiling paint and a sponge roller if you want to do it right. You can also get a spray can I think it is made by Rustoleum and use that for dark spots. I would use that as a base coat if I were going to roll it anyway.

yes you can paint over old popcorn. you have to use a sprayer. if you use a roller you will roll the popcorn right off the ceiling. NO GOOD