Did you ever think of marketing/selling your soaps(Because they are soft soaps) in an air tight plastic bag/wrapper kind of thing like 1kilo block of 3P, Cella or Vitos? I am not saying sell them in 1kg block, what about they are in an air tight bag of 100 or 200 grams or whatever, supplied with stickers to be used by your customers on their choice of tub/container. So there won't be need to manufacture or supply the tub. Empty multipurpose tubs and containers are sold everywhere and people can buy them according to their needs and wants.
This is just a thought, my opinion. I am not trying to impose any ideas.