I use relatively simple, non-toxic cleaners for everything, whether it be dishes, clothes, our bodies or general cleaning. Here is a recipe I found on the internet for washing woollens. I have adapted it slightly but you can also read the original here.
Rather than using soap flakes, I grated Sunlight soap.
2 cups grated soap
2 cups boiling water
1/2 cup methylated spirits
10ml eucalyptus oil
1 cup water, extra
Grate the soap into a large bowl and add boiling water. Blend thoroughly.
Add 1 cup of cool water and mix again.
Allow to cool a little before pouring the mixture into a suitable wide-necked container. I used an old Napisan container. It does need a wide neck as the mixture is quite firm when it sets so you need an old spoon to scoop it out.
To use the mixture I put about a tablespoon of mixture in a bucket with some hot water and mix until it is dissolved then add add more water until it is tepid and use this for washing woolen knitwear and other handwashing.
**EXTRA FRUGAL TIP**
Make sure you have some items ready to wash before you make up the mixture.
Rinse all of the utensils used in a bucket of warm water and the residue will be sufficient to make a solution of wool wash for your waiting clothes.