Black spots on Epidendrum, please help
 

Hi,
My Epidendrum has black spots. When I received it, it had this condition. I kept spraying it with Physan 20 and Neem oil. Now I am not sure if the plant is disease free. Some of the new growths have the same markings, but most look clean. I am also worried about this spreading to my other orchids. Should I keep spraying or throw out the plant? Someone please give me advice. Thank you