There are a few recipes available for laundry liquid, but this is the one that's worked the best for me.
To make the laundry liquid you will need:
60g grated castile soap
1.5 litres water
1/2 cup of washing soda
1/4 cup of borax
1 litre hot water
5 litres hot water
a large saucepan
a 10 litre bucket
a long-handled spoon
4 or 5 two litre bottles (you can use plastic milk bottles or similar)
Into the saucepan goes 1.5 litres of water and the grated soap. Warm over a low heat until the soap has dissolved. Then stir in the borax and washing soda. Continue to stir until the borax and washing soda have dissolved and mixture starts to thicken - sometimes this happens quite quickly, but it will thicken more has it cools so don't worry if it still seems a bit runny.
Pour one litre of hot water into your bucket. Then carefully pour in the soap mixture and stir well. Add the remaining five litres of hot water and stir again.
Pour into your bottles. Don't fill the bottles completely as the mixture can become quite thick so you may need to give it a good shake before using. About 1/2 a cup should do an average load.