I have some scratches on my newly brought panniers for my 1986 k100. the hinge broke on the bottom and half the pannier few off resulting in unsightly scratches. They are the black touring type . Any Ideas?

Use a small file and file the ridges along the scratches, that will attenuate them a lot and may even make them disappear depending on your filing skills.

Then some sanding.I have used the orbital sander on the larger surfaces but that can depend a lot on your finish on the lid, some aren't smooth so sanding too much could leave shiny spots.

That sanding will turn the black an ugly greyish color. First apply leather dye and let it dry real well. Will turn an even uglier purple black.

Then apply shoe polish, the paste stuff and buff to a shine. Finish with ArmorAll or any good silicone based protectant.

I have an old BMW lid I use for practices. I have tortured it a lot and found out that the cheap products work just as good if not better than anything else.