Saucha means purity of mind, speech and body. Being pure is not just at a physical level, but also in our relationships, and in our minds. Think of your body like a temple. The better you can keep it clean and healthy, the easier it is for your soul to fit in and to accept others. It also gives you another starting point for building good and working relationships that raise and balance you. The time you spend on relationships that lower you, or that does not give you joy and energy instead of spending on things that make you happy, is destructive. This is a well documented truth.
To follow a healthy diet for example, or taking care of your personal hygiene are parts of this concept. It also includes the cleanliness of the environment around the globe. How can you practice this concept when you have trauma and blockages in your body? Here I will give you a simple example. Purity for me sometimes meant that I got up from my bed, showered and got dressed. I, who come from Hungary really believe in the healing power of water. I performed rituals in the shower by dry brushing me from top to toe, lubricating me with oils that calmed me (lavender) and I immediately felt a bit better. For a while I have tested different oils that I bought in small packages, but today I know there is a whole movement around aromatherapy, ie the use of esoteric oils in daily contexts. Dry brushing as a ritual is an ancient method and you can find lots of descriptions on the internet. Then, when I finished, I could collapse again, but I had taken a first, cleaner step.