My first batch of home made liquid laundry and dish soap
Initially, I dropped a bar of Kirk's Castile into a black plastic whey protein jug with a gallon of rainwater, and put it in the solar dish I heat my daily 1 gallon of shower water with in hopes it'd dissolve so I could skip grating the bar. Despite the black jug getting a hole melted in the side (!) the bar did dissolve in a couple of days. I poured it, two more gallons of rain water, plus 1 cup each of laundry soda and borax into a scavenged plastic water bottle and set in the solar dish vs. simmering it on my stove. I believe today is day 6 and the ingredients have almost completely dissolved after 2 days of the jug just sitting on a glass table facing south. Next I add the last 2 gallons of rainwater, then store the liquid soap in Arizona Green Tea jugs rescued from recycle bins. Cheap is fun!