Griot's Iron Remover Not Working After a Year?

[Thunderchicken]

I wanted to ask whether anyone has experienced a failure of this product after storage for approximately a year? I purchased a large bottle last summer from Autogeek, used it in the fall & spring and took off lots of purple brake dust. It also had the featured stink. Tried using it yesterday and got no color reaction on any of the four wheels or adjacent panels. Noticed the stink is almost gone as well.

Does t his stuff go off, I don't see an expiration date on my bottle ..

Thanks -