Washing soda is a mineral, sodium carbonate. It is also known as soda ash.
Washing soda can be used to clean off oil, grease and dirt when laundering clothing and other fabrics.
Washing soda can be used to soften water and to boost soap.
Washing soda can usually be found in the laundry section of supermarkets and in some pharmacies.
Note: Washing soda is slightly caustic. As such, it is recommended that you wear gloves when handling washing soda and any product it is introduced to or made with.