Mix 2 tablespoons of unscented castile soap with about a 1/4 teaspoon of mica powder or a few drops of soap colorant.
Add 20 drops or more of essential oils or fragrance oils and stir well.
Apply a thin coat of the soap mixture onto a piece of the fabric stabilizer paper with the sponge brush.
Flip the paper over and repeat on the other side.
Hang the paper from a piece of string with clothespins to dry.
Once dry cut up the paper into small workable sizes.
Use a paper hole punch to punch out circles in the soap paper creating confetti.
Store the confetti in an airtight container or place in a bottle or bag for gifting.
Notes
To use simply sprinkle some of the confetti into a bathtub filled with warm water.You could try food coloring but it may not mix well with the oils and liquid soap.If you don't want to hang the paper to dry you could try letting it dry on a cooling rack or a clothes drying rack.You can use different shape paper punches found in most craft stores instead of a standard hole punch.You may find that the hole punch gets a soap build-up after so many punches. Simply run it under some hot water to remove the soap and dry well.