Q: How do I clean the orange stain from chili sauce from my solid-core sink? I have tried Bar Keepers Friend and bleach.
A: Describing a sink as "solid core" really is just saying it's not hollow. It's an accurate term for sinks made of cast iron or fireclay topped by a porcelain-enamel glaze, as well as for sinks molded from a variety of composite materials. But "solid core" usually shows up in product descriptions only for the composite sinks, especially when they are made with acrylic or other plastic resins and are not mostly stone.
If you have a glazed sink or one with a glossy sheen, stick to nonabrasive strategies. Depending on the sink materials, even Bar Keepers Friend and chlorine bleach could damage the surface. But you've already used them, so just think about what else you might try. You've used an acidic cleaner (Bar Keepers Friend) and one that's alkaline (chlorine bleach), so try something with a different chemistry: hydrogen peroxide, an oxygen-based bleach. Powdered oxygen bleach, such as OxiClean, is grittier, so the liquid hydrogen peroxide is safer. Use it full strength from a bottle you buy at a drugstore or grocery store; these have a relatively mild 3% solution, diluted in water.
But if your sink is a "solid-core" composite, chances are it doesn't have a shiny surface that you need to protect. In that case, you can probably scrub away the stain, leaving fresh, unstained material at the surface. Start by testing your procedure to make sure you aren't creating noticeable scratches. Test in an area that's not too noticeable, such as a small section of the interior sink wall closest to you when you are facing the faucet. Start by using a mild abrasive, such as Bon Ami, and a sponge. If that's not aggressive enough, advance to a grittier scrub powder, such as Comet, and a green Scotch-Brite pad, like you would reserve for pots. The less glossy the existing surface, the easier it will be to blend your stain-removal efforts with the rest of the surface. To create an even sheen, you'll probably need to scrub the entire surface, not just the stained area.
One company that emphasizes the "solid-core" nature of its composite sinks is Vigo Industries, which molds them from what it calls "Vigo Matte Stone," which it describes as "an ultra-durable PMMA acrylic composite solid surface designed to look and feel like carved, polished stone." (PMMA stands for polymethyl methacrylate, a chemist's way of describing acrylic, which is a plastic.) The matte surface "makes for effortless cleaning," the company says. "Stains can be quickly removed either with standard household cleaners or by buffing with sandpaper." The company includes a piece of 400-grit sandpaper when it ships a new sink.
Yet in a blog post on the Vigo website, the company doesn't mention sandpaper when responding to customers' concerns about food stains. Instead, it recommends bleach, Soft Scrub and a Scotch-Brite pad and warns not to leave the cleaners on the surface for more than 15 minutes. "There are certain acidic compounds such as coffee and spaghetti sauce, etc. which stain regardless of the material they come in contact with," the company's blogger wrote. "A product like BeesWax can be extremely beneficial to you to keep your sink impervious to staining. It should be applied once a week to form a barrier which prevents stains."
If you decide to try waxing your sink to make it more stain-resistant, buy a piece of pure beeswax, which is usually yellow. (A one-ounce block costs $2 at crystalsrawhoney.com.) Work when the room is at least 70 degrees, ensuring that the wax and sink are both a little warm. Rub on the wax, then buff with a soft cloth. One website that gives advice about coating copper sinks with beeswax recommends spraying the sink with warm water to warm it and the wax coating before giving the surface the final buffing.