We are in preproduction of our first feature film. I have a question about the use of company and famous peoples names. There is a character in the script named Coke Machine [because he is big like a Coke Machine] and a box is found labeled CASH but when it is opened it is full of old Johnny Cash albums. We do not plan on using Mr. Cash's music but his name is mentioned and the albums are seen on screen. I realize I could change Coke Machine to Ice Box or something, but was wondering if I would need permission to use Coke Machine and Johnny Cash and if so how would I go about doing it? Also should I expect to pay for this. I plan to sell the DVD's myself and hope to get into some film festivals with it. Any information would be greatly appreciated.