How do I clean a black gas cooktop without scratching it?

I have a black glass top if that is what you meant. The first thing I learned is keeping it clean and never letting the crud build up..There are many cleaners out there but I have found a good wipe after top cools and then a layer of baking soda and a damp rag placed over that. Let it set for a while then do your wiping away of residue. Use nothing that scratches the glass.

Maryann: I've actually had fairly good luck using a Magic Eraser! (...and some elbow grease)

I use Weimar Glass Cook Top cleaner. If there's any crud around the burners I put the cleaner on and then use a single edge razor blade to scrape it off then polish with a soft rag. Hope this helps.

Baking soda is a very soft abrasive that I use to clean my stove top