I use half bar of soap,at present i`m using sunlight as it has a lemony smell,
1 cup of washing soda crystals,i use the empty tub from the borax to measure as its about the size of a cup,
100g tub of borax,(a cup)
3 or 4 of the empty washed 2 litre plastic milk containers.
first i put a kettle of fairly hot water into a stainless steel saucepan(large)and add the above ingredients to it and slowly add more water, stirring with a wooden spoon from time to time for about 20 mins,when all the ingredients are dissolved i let it cool down and divide it between the milk containers then top up with warm water till nearly full,give a good stir with the handle of your wooden spoon,
there thats it,you can add oils to give it scent,or use a different soap,i`ve used cheap lidl soap that worked well for me,and i`ve also a batch i made from carbolic for my sons bedding as he wets occasionly,and i`ve also put different oils in each of the 3 containers,the last batch i did yesterday i put into 3 containers but it has come out really thick so next time i will put it in 4,it varies ,the soap makes a difference,but i just squeeze the container and cut a slice off,it works well,my washing is good today,perhaps you may find a container with a wider spout?don`t go for a container with a smaller one,you`ll never get the gloopy stuff out!this rarely bubbles when washing ,a friend of mine puts a squirt of washing liquid to give it a few bubbles when washing as she feels it looks better,i don`t bother,its what you expect it to look sometimes

good luck,happy washing.its so cheap and you can vary it when you get used to it,