Found this recipe for bath bombs
You'll need:
1 1/2 cups bicarbonate of soda
1/2 cup citric acid powder (use fine grade, available from chemists or pool supply shops)
Sieve
Potpourri or herbal teabags such as chamomile, lemon, rosehip or peppermint
An essential oil such as peppermint, lavender, geranium
Sweet almond oil (from chemists)
Food colouring
Rubber gloves
Moulds from craft shops
Step 1
To make the base mix: sieve the bicarb soda and citric acid powder into a large dry mixing bowl. This will make enough for four bath bombs.
Step 2
To make one bath bomb, transfer 1/2 cup of the base mix into a medium bowl and stir in the contents of a herbal teabag or other dry ingredient such as potpourri. Set aside.
Step 3
In a small bowl, combine 6 drops of essential oil of your choice, 1/2 teaspoon of sweet almond oil and 8 to 12 drops of food colouring - or until your desired colour is reached.
Pour this mixture into the bowl containing the 1/2 cup of base mix and stir quickly with a teaspoon so things don't start fizzing!
Step 4
Wearing rubber gloves, continue to combine the ingredients with your fingertips until it starts to clump together when compressed in your hand. It's essential you do this with your fingertips, not a spoon, so the liquid is distributed evenly. The mix is now ready to go into a mould.
Step 5
Wipe a little sweet almond oil inside the mould.
Fill the mould with the mixture, packing it in firmly.
Make the other bath bombs with the remaining mixture, working with 1/2 cup at a time.
Leave the bath bombs in their moulds to set for at least 24 hours (36 hours is even better).
After they have set, turn each mould over and bang it firmly once on a flat surface, then gently ease out the bath bombs