14+ Fast & Easy Laundry Detergent Recipes You Can Make ...- how to make washing powder lavender washing powder lemon powder ,Grate the Castile soap bar in a food processor until it resembles a fine powder. Mix in the washing soda and Epsom salt. Pour in the vinegar while mixing. Blend in essential oil to help create a pleasant scent. You can skip this step, but we like to use lemon, orange, or lavender.14+ Fast & Easy Laundry Detergent Recipes You Can Make ...Grate the Castile soap bar in a food processor until it resembles a fine powder. Mix in the washing soda and Epsom salt. Pour in the vinegar while mixing. Blend in essential oil to help create a pleasant scent. You can skip this step, but we like to use lemon, orange, or lavender.