I'm going to assume you're making a protein-based soup/broth (chicken or beef). When you put meat into the water and simmer it, "scum" will rise. It's juices and some fat, and there's nothing unhealthy about it- but it doesn't make for a pretty, clean-looking broth.
I would need more information about which soups you're making so I can give you more precise feedback. However, I've been making chicken soup for almost 50 years, so I'll address that. Here's how I make chicken soup:
1. Wash one chicken in cool water and drain.
2. Cut the chicken into quarters to make it easier to handle. If you don't know how to do this, it's okay to cook the chicken whole. Adding extra chicken necks and gizzards is fine, but do NOT include any of the liver. It'll make the soup cloudy.
3. Put the chicken into a 4 quart pot that has a lid. Cover the chicken with cool water.
4. Bring the water just to a boil, then turn the heat down until the liquid "shivers".
5. After 20-30 minutes, take the chicken pieces out and set them aside. You can skim off the grayish protein bits with a skimmer, but the most effective way to make the broth clear is to strain the broth. Fold two or three layers of cheesecloth and put it into a strainer (the kind that looks like a window screen is best). Set the strainer over another pot or large bowl that'll hold the broth. Pour the broth slowly through the strainer.
6. Return the broth to the pot. You can rinse off the chicken pieces before adding them back into the pot.
7. Add vegetables: 1 large, peeled carrot (whole); 1 small bunch of fresh or dried dill stalks; 1 small leek (well-cleaned and trimmed), cut in half lengthwise, then into 3" lengths. You can also add a whole, small, trimmed onion, some peppercorns, trimmed parsnips, etc. Some even add a pinch of saffron, but I don't use it.
8. Allow the soup to simmer, partially covered, at least one more hour. You can remove the chicken after that time, bone it and use it in the soup or in chicken salad, etc.
9. Season to taste.
The process for beef soup is similar, but the beef is browned before you simmer it in water.