Weird marks on molds after when working with hollow molds.

I have recently ran into a problem with some of my molds.After de-molding I am getting weird spots that don't really qualify as water marks. (see attached) I have tried polishing molds, moved the temperature of the work environment to as high as 72 F and as low as 60 F, preheated the molds, washed and did all of the above. The problem first occured after the molds were washed before switching from milk chocolate to dark chocolate. This is not the first time that such a switch too place but a first time that I have encountered such a problem. My molds are all hand painted so I cannot pre-heat them too much anyway just to about 75-77 F. The image attached shows a cloudy area in the middle of an otherwise shiny object. Any suggestions?

Did you let your molds air dry the last time you washed them? If so there could be minerals from the water left behind that polishing the molds might not remove. Stains like this can be difficult to remove. I've never done it with chocolate molds but you typically have to use a white vinegar and water mixture. In this case, I'd probably just soak the molds in this mixture for a while and then rinse welland hand dry.

Did some more experimentation today and actually pre heated my molds, the marks went away so I guess these are water spots. That opens another issue for me-If i can't decorate it I won't make it. How do I decorate it and pre-heat it at the same time?

Are you using colored cocoa butter?

No, not on these.