I am a young 48 yr old, and my skin is beginning to look dull and dirty, what are the best creams to use to make my skin look cleaner

As you get older your skin does not shed as quick as a youngster.

Have you tried products containing AHA? They are great for older skin types. It exfoliates the skin therefore revealing the new brighter skin underneath. A good product is ALPHA H Liquid gold. When you use products containing AHA, remember to use spf everyday, at least 15 as the skin becmoes more sensitive to the sun.
If you can't find ALPHA H, then look out for products that claim to brighten the skin, and look for the key ingredient Glycolic acid or lactic acid as they are both AHA.