2) Film studios used to have their addresses listed but some no longer
> do. Particuarly, the WB TV network refuses postal mail and has
> everything returned to the sender.
Actors sending in pictures and resumes to film/TV studios often send them in clear plastic envelopes.
Associated Bag makes a nice plastic envelope/bag that I have used instead of #10 envelopes. I fold over open end and use the mailing label and self-adhesive stamp to seal it closed.