What chemicals can change the color of gold?

I was cleaning the showers in my house without gloves and some of the chemicals got onto the rings. My 10k rings changed to a dark gold color but the 24k did not change color. I was working with Tilex products and some industrial strength disenfectants. I was wondering what changed the color and how I can change it back other than taking it to a jewelers to do a normal cleaning. A best answer rating will be given for a complete, thoughtout answer with correct grammer.

Thanks!