Sunny bronze clay fail - why?

[AgplusAu]

Hi - I cast a leaf about 2 inch long using sunny bronze clay - fired it for 30 mins on steel mesh over a camping stove. It was so black I then put it in dilute sulphuric acid pickle to clean it up. What happened then was awful - the piece disintegrated and turned the acid blue.
Two questions: why did it go so wrong?
Can I use the acid for pickling sterling silver now or will it copper plate anything I put in it?
PS I have successfully cast other items using PMC silver clay - have never used the bronze before this though

[Dennis]

I dont do clay, but if it disintegrated in your pickle it was incorrectly fired, either too little or too much. You can experiment to get it right, or refer to to your supplier.
Can you re-use your pickle on silver? Put in some scrap and see. Dennis.