Citric acid and its diammonium, potassium and sodium salts are all used to help preserve cosmetics and personal care products by chelating (complexing) metals. Citric acid and its salts are also added to cosmetics to help adjust the acid/base balance.
Bath bomb recipe
100g bicarbonate of soda.
50g citric acid.
25g Epsom salt (optional)
2 tbsp oil – such as sweet almond oil, coconut or olive oil.
¼ tsp essential oil, such as orange, lavender or chamomile.
a few drops of liquid food colouring.
orange peel, lavender or rose petals, to decorate (optional)