Rhodium

Rhodium is a chemical element that is a rare, silvery-white, hard and chemically inert transition metal and a member of the platinum group. It has the chemical symbol Rh and atomic number 45. Naturally-occurring rhodium is composed of only one isotope, 103Rh. It is one of the rarest precious metals and, with a price of about US$80,000/kg in 2010, is the most expensive member of that class.

Cleaning
100 gms soapwort root (Saponaria Officinalis)
 * Mechanical
 * Chemical

1 lit water

Mix root and boiling water i  pyrex jar,cover, after 10 minutes it is ready to use.Fresh  solution is pH neutral,few days old is  slightly acid (pH 5).

According to:

Personal experience


 * Electrochemical
 * Ultrasonic
 * Laser