Casting a passion flower

When casting a passion flower in centrifical casting, the sterling
silver has a deep brown color that I am having difficulty rmoving. I
have done several others without this problem. Could the silver have
been overheated? Any other ideas of what caused this? Any
suggestions about how to get it back to the silver color? HELP!!!

Attn. Marion- Greetings; Possibly your flower was not completely dried
out. Or you need to burn out longer. Make sure your sterling shot is
‘fresh’ with plenty of ‘casting flux’… One method to clean up your
casting is to boil Sulfuric acid and bathe casting until clean.
(safety precautions in force) Or better yet is to ‘electro clean’
your casting. The materials for this process can be found at:
www.swestinc.com If you order, make sure that you get full
instructions.–(fact sheet) Take care-- Dave.(18k)