The best places to look are in the laundry detergent aisle at the grocery store or in big-box stores, hardware or home improvement stores, international grocery stores, and pool supply stores. And if you still aren't able to find it locally, you can buy it from Amazon.
Washing soda is often sold in a large yellow box. Arm & Hammer is the most common brand, so look for that red logo. Arm & Hammer has started putting washing soda in an orange box that looks almost exactly like its baking soda box, so keep an eye out for either box design.
What Is Washing Soda?
Washing soda—also known as sodium carbonate, soda ash, and soda crystals—is a white, odorless powder that looks similar to baking soda, though the texture is slightly grittier. It has many uses, including in cleaning products.
Naturally Occurring Substance
Washing soda is a naturally occurring substance derived from the ash of sodium-rich plants. Sometimes it's manufactured synthetically. But whether nature-made or human-made, it's just a chemical compound consisting of sodium, carbon, and oxygen.
Take care to store washing soda in a dry area. It absorbs moisture readily and will turn brick-hard when it does.
Washing Soda Uses
Washing soda is used in many commercial products that include detergents and toothpaste. It has just as many household applications and is frequently used to soften water, make cleaners, remove laundry stains, and fix dyes to a piece of fabric. It shows up often as an ingredient in homemade laundry detergent and dishwasher detergent.
ArmandHammer.com has numerous ideas on how to use washing soda to upgrade your laundry. Arm & Hammer suggests adding it straight into your washer at the beginning of the wash with your regular laundry detergent to enhance cleaning and freshen your clothes or linens, to do the hard work on heavily soiled clothes, or to soften the water if yours is hard. You can also put it to work on spots and stains with a pre-treat paste or as a pre-soak. In all uses, check the instructions for your washing machine before using washing soda and be especially careful with high-efficiency machines.
It also works its magic on hard-to-clean items such as ovens, stovetops, and stoves; outdoor furniture; window blinds; and silver, copper, and gold items. It will even clean up grease and oil stains in the garage. You cover the stain with washing soda, sprinkle with water, and let stand overnight. The next day, scrub with a brush and hose off.