Rust Trouble - Help Please

eldiabloz wrote:It may be an indicator dye. Try this. Determine if your rust spotter is alkaline or acid based. Try using the opposite. If it's acidic in nature try some ammonia. If alkaline try an acid based product, maybe some glycolic acid or whatever you have that fits the bill. Might work.

milspec6 wrote:Turned Blue?  Suspect that there might have been some removal attempts by the owner and it was not chemically compatible with your rust remover.  It sounds like a chemical shift.

Test for ph and go from there.

dp1 wrote:Circular rust, is it from plant pots ?
If it is, I'm almost willing to bet you that the customer was using some kind of plant food to feed that particular plant, I would rinse it with water first before testing the ph or neutralize things, I like to keep things as simple as possible, but if it doesn't come clean then you'd have to do what Rob and Eldiabloz were suggesting, good luck and don't forget to share your experience here after you're done :-)

milspec6 wrote:DP is the man, seen it all.  Most plant supplements are iron based, so the rust makes sense.  There are also ph modifiers at work...sulphur, lye, etc.  Could be any one of those things.

I still lean towards a failed attempt by the owner.  I have seen a lot of odd colors arrive after they used an "oxy" product on it, you just might be the unluckly one to activate their mistake.