Updated March 18th: 2020 – they have not published in over a year. I would consider them defunct. Do not submit.
Clean Teen Publishing is a small publisher started a number of years ago. They publish print and electronic versions of books. All of the books they publish are aimed at teens. Their selling point, and the reason they are named what they are, is that all books come with a really clear rating system, that they refer to as content disclosure. This is an unusual concept, and while I can see how it would appeal to parents, I am not sure how attractive it would be to most teenagers.
This is the way the rating system works. They have three levels of rating, the first is YA E which is appropriate for everyone, including advanced readers, ages 12 and under. The second is YA which is appropriate for young adults age 13 and over. The third is YA M which means the book is written for a mature young adult audience. The system for how each books get rated is really clear, and there are image indicators on all the covers of why the book got the rating it did (for example a miniature gun indicates violence, which on a YA E book could mean a punch and on a YA M book could mean death). To learn more about the system read the full guidelines here.
The publisher has good distribution in bookstores and libraries and seems to have established a good, although often series dependent strategy for selling eBooks on Amazon. Their books have received a fair amount of attention from reviewers of all kinds. Their covers are generally good. Their website is also orientated towards readers, not writers, always a good sign.
To learn more about how their submission process works, go here.