Like the title says "One can of Richard Petty's racing exhaust" on front. It looks old. Never seen anything like it guessing its from early on in his career. word for word this is what it says on the back:
"Directions- To be handled by official race fans only. If can must be moved, move counter clockwise direction only. Failure to follow these directions could cause a sever accident and-or a condition know as BLACK FLAG."
"Caution: do not open can- Valuable souvenir fumes will escape and be lost forever. In the interest of ecology, do not mix contents of this can with northern air."
"Warning- Constant exposure to fumes might cause RACING FEVER."
"Antidote- Regular attendance at grand national races will relieve pain, BRAKE FEVER."
"Actual contents: Air"
To the side a little bit it has a "to" and "from" section along with a spot to put stamps. Guessing its some sort of post card.