How do I remove burnt on grease on pots?

Oven cleaner would be my first option. Steel wool pads or the scratchy pad may be required. Wear rubber gloves.

Scrub with baking soda and water or Bar Keepers Friend.

I would recommend you soak the pots by putting in some hot water and adding a little Dawn Dish Washing liquid. Let this set overnight. If any of the grease has loosened, scrap off what you can using a single edge razor blade.

Then it is just a matter of keeping at it until you get it clean. Bar Keeper's scrubbing powder works great to finish up cleaning the pot.

GOOD LUCK!

I use comet cleanser and green scrubber sponge then go over with some dawn dish liquid

Cerama Bryte makes a stainless steel pot and pan cleaner. Works like a charm. It's similar to Bar Keeper's Friend.