And a bottle to mix and store it in.
Mix it up to 1 part soap and 7 parts water. I pour the bottle of soap in a 2 liter bottle and then add 7 bottles of water to the bottle and shake it up. Wait until those bubbles from shaking it go down and its ready to use.
Tip- I use Softsoap because its cheap and often has coupons making it really cheap if not free. I stock up then and always have it on hand when I need it. Two bottles of Softsoap and the water to mix it will fill a 2 liter bottle if you don't want to measure out all the water one bottle at a time.