Citric Acid is an essential DIY ingredient for DIY cleaning recipes.  Citric Acid is a  alpha hydroxy acid and a natural preservative that exists in many different fruits, vegetables etc. 
Citric acid is also used in personal care DIY products to adjust the ph or acidity or promote skin peeling and re-growth in the case of anti-aging products.
Citric acid works well as a colour brightener and water softner in DIY laundry powder recipes.
 
Use Citric Acid in DIY recipes below;
DIY toilet cleaner fizz recipe here
DIY laundry powder recipe here 
DIY bath bomb recipe here