Good Luck!! I regret buying my Silgranit because of the problems cleaning it. Mine is white. I swear it absorbs stains. Anyway, I've used many things, BarKeepers friend, Ajax etc. You might try a light spraying with pure bleach I've done that to get a rust stain out that a plastic coated grate left behind when it failed and that STILL didn't get the rust stain out. I'm told that Blanco, the manuf puts out a cleaner but I haven't contacted them yet or tracked it down since I don't have a lot of confidence that they have anything stronger that would actually work.

Can you let us know if you come across anything that works?

I use Mr. Clean Magic Erasers, works great.

I have this exact sink. I love the farm style, it is roomy and deep. Though I do have hard water, and find my sink with a white film on it. I have also tried the mineral oil, but I am afraid of making a build up.

I will try the magic erasers, but am afraid of using them on many surfaces because they take the sheen off.

I might call Blanco and have them send me some of their cleaner. Or, better yet, the guy who installed my counter tops, who talked me into this sink, maybe if I call him and invite him out to scrub it, he won't be so pushy with a product next time.

Last time I Magic Erasered my sink I followed up with Sprayway Stainless Steel Cleaner and Polish, because it contains oil. My sink looked fantastic after that.

I've had two and my daughter one silgranite black sinks from different manufacturers. I've used mineral oil very satisfactorily to keep it looking like new. I let it sit for a few minutes, then clean with paper towels and buff it. Absolutely no buildup.

I'm in a condo now, and was considering changing from black to white, but comments here tell me I should stick with black.

Always glad to see that Houzz readers are still here with help when needed.

P.S. New owner of my kitchen loves the sink as well.

I've got the black sink, and clean it first with whatever cleanser works. Right now I'm using up the Pink Stuff and using a Scrub Daddy sponge to clean it. Then I dry it off, to a point, doesn't have to be bone dry.

After that I pour some vegetable oil into it and wipe with a paper towel. It restores the luster and beads up the water for a while. I probably do it once a month. You get the hang of how much oil to use after using it a few times.

I like this sink because it never shows scratches like my stainless steel or white sinks have in the past.