Just the other day I bought this cleaning product called "Bar Keeper's Friend." It comes in a can like Comet, as a matter of fact I believe it was next to the Comet in the store. This stuff it amazing!
I have white countertops in my kitchen and I had a section that was stained by something. I have no idea what (I have kids lol) it was stained from but I had tried everything I could think of to get the stain off. So I was buying my cleaning products and I saw that stuff. I read the label and it is good for a lot of different surfaces so I thought I'd try it out. I am so glad I did!

I sprinkled a little of it on the stain and then sprinkled a little water on it, making it a paste. I let it sit for about a minute and then I wiped it off. My counter looks brand new! I am so impressed with this stuff.
It says it can be used to clean grout, tubs, sinks, stains in plastic dishes, stoves, ceramics, metals and so much more.
I am going to try in some of my white plastic bowls that have had sauce in them and are now stained.
This stuff only costs about $2.00 and it's well worth the money.