As you can see in the picture to box did blacken after firing but as its name claims the foil did not flake at all. As you can see in the picture below you can rub the box as below and nothing rubs off.
To answer the question as how did the items in the box turn out? Well in all truth they did not sinter properly but it is probably due to the type of carbon I used. When I went to buy carbon this week they were out of the coconut carbon I usually use. Alas, I bought the coal carbon which is used for firing regular BRONZCLAY, when I went to fire I reviewed the directions for FAST FIRE BRONZCLAY and noted the they recommend using the coconut carbon. I decided to try it anyway ('cause I like to test these things). Well, you shouldn't use coal carbon, it didn't work.
Needless to say this should be a topic for another post, picking the right carbon for you base metal clay. Now I have a research project!