liquid dish detergent and a fingernail brush.

My 99 had black seat belts. They didn't show dirt even after 10 years and I never cleaned them. But, I now know that they must have been pretty dirty. My 08 has silver seat belts and they do show dirt. I tried to clean them for the first time today. I first used Johnson's baby shampoo just be on the mild safe side. Not much happened. So, I went nuclear with p21 citrus degreaser. A little cleaner, but not what I expected or want. Any suggestions?

Thanks, Bob

1999 Arctic Sivler/black/black (sold)
2008s Silver/black/black - so predictable
2011 Outback
8/24/2011 first Grandson

or maybe a foaming upholstery cleaner.

or Mr.Clean Magic Eraser?

I've used 1 and 2, with some success, haven't tried #3.