I’ve used Barkeepers friend without any issues. Those black marks would probably be removed with it.

Almost a year with my all gas 30” range and I love it more every day. The oven may be the best oven I’ve ever used. I’m baking pizzas on a steel in it in 3 and a half minutes. Using a Combustion Inc. Predictive thermometer I can see how crazy evenly it heats too. Stove top is wonderful too, just wish it had another 21k btu burner with the triple ring. So even and hot. My copper pots sing on it.

The LED is more fun than you’d think too!