Castile soap – a centuries-old solution

DATE:  9 June 2025
SUMMARY:  For those of us drawn to natural and sustainable products, Castile Soap stands out as a true gem. With its rich history and versatile uses, this plant-based soap has been cherished for centuries. Origins Castile soap traces its roots back to the 12th century Spain where it was developed in the Castile region.  Inspired by…

For those of us drawn to natural and sustainable products, Castile Soap stands out as a true gem. With its rich history and versatile uses, this plant-based soap has been cherished for centuries.

Origins

Castile soap traces its roots back to the 12th century Spain where it was developed in the Castile region.  Inspired by Aleppo soap – a traditional middle eastern product made from olive oil and laurel oil –  Castile soap was originally made using just olive oil.

It became popular across Europe, initially as a luxury item favoured by royalty and the upper classes.  Its appeal endured, due to its gentle yet effective cleansing properties.

Modern versions incorporate other plant-based oils such as coconut, hemp, and jojoba, which enhance its lather and moisturising qualities.

The Sesi brand on sale at Waste Nott is carefully crafted from sunflower and coconut oils, without any added scents. The base is derived from organic oils, boasting a natural translucent pale yellow hue.

Benefits

This centuries-old product has huge relevance today as we seek natural, sustainable alternatives to synthetically produced soaps. Here are just a few of the benefits:

  

  • Natural and eco friendly: it’s biodegradable, and free from synthetic detergents and harmful chemicals. The fact that it’s plant-based means it’s more sustainable.  
  • Gentle on skin: free from harsh irritants, it’s suitable for all skin types including sensitive skin, for those with eczema, or anyone seeking a mild cleanser.
  • Moisturising and nourishing: it contains oils rich in nutrients that help hydrate and nourish skin, and unlike many commercial soaps, it cleanses without  stripping away the natural oils.
  • Customisable: often sold in pure, unscented form, it allows you to add your favourite essential oils. Eg lavender for relaxation or tea-tree for anti-bacterial properties.

Uses

Castile soap is hugely versatile. It can be used as a body wash, shampoo, household cleaner, pet shampoo and a natural pesticide for plants. With just one product that does all this, you can minimise clutter and simplify routine.

We asked some of our team what they use it for, and this is what they said:

“I’ve recently used it successfully as stain removal on clothes”, Jude, volunteer

June Burgess, volunteer in the Waste Nott shop

“It’s great for removing tea stains from china cups.” Joan, volunteer

two china cups

“In the shop I use it to remove sharpie pen marks from the counter surfaces,” Ian, shop manager

Ian, shop manager, in WasteNott shop

“We wash our dogs with it,” Anne, volunteer

How to use Castile soap

Always check the label for dilution instructions, as some formulas are more concentrated than others.

For the Sesi variety on sale at Waste Nott, it’s as simple as diluting it for your desired purpose.

For example:

  • Body Wash: Mix 1 part Castile soap with 2 parts water.
  • All-Purpose Cleaner: Combine 1 tablespoon of Castile soap with 1 litre of water.
  • Shampoo: Use a small amount directly or dilute with water for a gentler cleanse.

A centuries-old choice for a modern world

Castile soap’s lasting popularity is a testament to its effectiveness, sustainability, and adaptability. Whether you’re looking to simplify your cleaning routine, embrace a more natural lifestyle, or reduce waste, this soap is a timeless solution that aligns with modern values.

So, why not give this centuries-old wonder a try? Your skin, home, pets, and the planet will thank you!

Find out more about Castile soap and our other products here