And if that doesn’t do it, try the trick I learned for cleaning the cutting boards at Subway. Lay down paper towel over stain, pour straight bleach on the paper. Let it stand overnight. The paper keeps the bleach in place and it won’t dry as fast. A little harsh, but it works.
We had plastic cutting boards that covered the entire length of the counter that would become stained and dirty through the day despite being wiped down after almost every order. And since sanitization is vitally important at a restaurant, they needed to be cleaned somehow. The boards would be rinsed and wiped down every morning before use.