Make a paste of vinegar and baking soda.
Soft Scrub, put grates in dishwasher , polish off with glass cleaner.
DAWN ULTIMATE & A BLACK GRILL BRUSH. Run a sink full of Dawn water (heavy on the Dawn) & dip your grill brush in. Scrub your stove top until it shines. Wipe off with a dry paper towel. The scrub brush is strong & will usually grab whatever grime is on there. The Dawn will cut through it so the brush can scrape it off. I do it whenever mine gets baked on or splattered on & it works fine. AFTERWARDS, go to Walmart & in the cookware section, they've got little tin plates that go right under the burner to collect the grime so you don't havta work hard next time. They're usually 10 for $1.oo -$1.50. Cheap & disposable!! They sure help.
Depends on what type of materials it is. When I moved in, the gas cook top was disgusting. I scraped off as much as possible with a plastic scraper. Then I spray degreaser and let it sit. Be careful to get one that is safe for appliances. I like Fuller's products. Then I wiped away with paper towels. Repeated a couple of times. Then wipe down regularly with warm soapy water, blue Dawn, to maintain the clean top.