In photography, sometimes 'clean' can mean a simple or minimalistic photo and 'dirty' can mean a busy or visually complicated photo. What is too much and what is too little? It is a highly subjective topic and what might be too busy or too plain to you, may be visually appealing to someone else.
Something to consider when taking your photograph is to ask yourself what is 'my story' and is there a better way to compose it? Are there distracting elements in my frame that are taking the viewer's eye away from or compteting with my subject? Are you 'stuffing' your scene with too much information, or does that added stuff add to your story? If you are using mutliple subjects, try to make sure they work together and assist each other. On the other hand, If you are taking a minimalistic photograph, you need to make sure that the subject is interesting and comfortable to look at. It is a fine balance!
I am guilty of adding way to much information into my photgraphs, but I am guilty also of loving something really eclectic and fun! I enjoy both 'dirty' and 'clean' photographs. Today take either a dirty or a clean photograph, or both!