1. Fluids! Coming into contact with bodily fluids, especially blood, can be harmful. It can carry disease and pathogens that you just don't want on or near your body!
2. Invisible to the eye! If you don't take care of all of it, you can still receive harmful effects. This means if you try and clean it and leave behind any traces of the scene (even germs and pathogens you can't see), your home won't be as sanitary as you think it is. You know how they say won't you don't know won't hurt you? Well in this case, it can.
3. Don't stress! While you may be worried that you can't afford crime scene cleaners, your insurance will usually take care of it! Don't let this detail keep you from getting the professionals in the door!
Never try to clean a crime scene yourself! You'll be happier, more sanitary, and less stressed when you let the professionals come take care of it.