What type of nozzle is it?
If the nozzle has a bit of tube sticking out the bottom that fits into a hole in the can; swap the nozzle for another that does work. If nothing comes out; the can is stuffed.
If the nozzle fits OVER a protruding tube then carefully press the end of the tube against a convenient flat surface (annoying neighbors fence, XR8 in a disabled parking space, Labour politicians forehead etc); if nothing comes out, the can is stuffed.
Please don't attempt to push anything into any part of the can. The valve mechanism is not accessible in any form from the outside; if you start poking sharp things down there you run the risk of punching through the valve seat permanently. At the absolute best that will be very, very messy...
Nothing succeeds like a budgie without a beak.