How do you clean the dirty zipper area on a SLG

Hi there. I’ve managed to lessen the zipper grime by using a toothbrush with a tiny bit of water and soap (Woolite Zero, for delicates). I didn’t saturate the brush at all and was careful about getting close to the leather. And try to stay only on the fabric. I used a baby toothbrush because it was small. I can’t say it was a remarkable improvement but it did look a bit better. I never took any pictures, sorry... Hope that helps...