I buy Bar Keepers Friend at my local Walmart, the liquid type works wonders for cleaning the soap scum from your tub also... Any where there is grease buildup, I have a bottle in each bathroom and the kitchen. Love it.
I use non-flamable engine degreaser, dilute as instructed, let it soak and take a soft scrubbing pad to it. It really smells good too. I have also used grate cleaner that you would use on your grill on my stove top, but the degreaser did a better job.