I was cleaning a corny with about 1/2 scoop of oxiclean in 5 gal of hard tap water from the bath tub. I was planning on letting it sit for 30 min then washing it out but got distracted and 3 days pasted with it sitting in there. Finally remembered it and dumped it out and washed the keg. Concerned that the oxiclean may be bad for stainless steel I hit the forums to see what people had to say. Seems like there is a split decission. Some say it is 100% safe even for long soaks, some say it will pit and tarnish the stainless steel.
To go a little deeper lets dive into what oxiclean really is (MSDS):
Sodium carbonate (also known as washing soda or soda ash) - used as a water softener at high concentrations in stainless steel water tanks, not going to pit stainless but will precipitate out metals in water.
Sodium carbonate Peroxyhydrate: Breaks down to produce Hydrogen Peroxide (H202) which further becomes 02 and H2. H202 is can be stored for years in SS tanks and only at VERY high concentrations and temperature does H202 cause harm to SS, not going to pit SS at the concentrations in oxiclean.
Ethoxylated Alcohol C12-C16 used as a surfactant and has oxidation qualities but is harmless to SS in the quantities in oxiclean.
Now lets look at the properties of SS that make it rust resistant. Stainless steel's corrosion resistance is due to a thin, chromium-rich, transparent oxide film on the surface. This protective film develops when more than 10.5 percent of chromium is present in the alloy and when the gas or liquid environment the stainless steel is exposed to provide oxygen to its surface. Therefore oxidation should help preserve the properties of SS. Bleach however is terrible for SS as the Chloride ions attach the oxide film allowing for corrosion. Oxiclean veristile does not contain Chlorine.
In my case I have some mineral build up which was most likely precipitated from the hard water and Sodium carbonate. I have not had a chance to acid wash this corrosion away but I see no signs of corrosion or pitting.
A couple of side notes most cleaners such as oxiclean and even bleach loose their harmful properties after 24 hrs. If you dont believe me take some bleach and dilute it to 10% in tap water. Wait 24 hours and smell it and try using it on something with a pH indicator. It will not have anywhere near the affectivness as fresh dilute bleach. Some people have stated that they ruined a stainless steel bowl and the like with concentrated oxiclean which may have been an old formulation containing chlorine. It is also possible it was a cheap bowl and wasnt true high quality stainless steel like our expenisve used cornies
As always I am open to debate and would like to see some well built "no your wrong" comments.