If it were easy, everyone would get a trophy:)   Wow- sorry I have to get off this soap box..  

I later figured out that the soap/shampoo over time reacts chemically with the copper line and corrodes it.That is all I can come up with at the moment, but gives you a few more ideas before you open up walls.

If there is any mold there, it's because the walls or pipes or conduit are dirty, and the mold is growing on that dirt.Dawn (or similar dish soaps) increase the surfactancy of water.

You'll find you have to think FOR THEM.If there is a dishwasher-know in advance they think ALL SOAP IS CREATED EQUAL and every new tenant you get is going to use laundry or liquid soap to suds up and flood the kitchen  via a dishwasher.So lots to do even when you so carefully choose the right investment by the numbers---all these PREVENTABLE expenses can nix your best calculated proforma.Best Regards to you-- it's fun, exciting, never boring and can be extremely profitable : )

If not regularly, well cleaned the soap scum builds up and the bottom railing gets real bad.

It comes with: hedonist chocolate, a neighborhood dog dish & nalgene bottle, locally made soap, a free drink from the local pub, a history book on the neighborhood, and a few other trinkets.

I was headed toward the wrong soap box.Don

(food, shelter and means to protect it as well as water, and barter items such as soaps, spices, matches etc) You listed my reason for gold/silver in your own post "you might be able to buy enough food to feed your family for a week with that ounce of food" .

One factor is that they are using cheap materials to clean, water and soap.

I will also lay out a cutting board with piles of aromatic spices.In the bath, decorate with decorative bottles, pot pourri, aromatic soaps.