I picked up a can of the 505 to try for the first time yesterday. Spent the last hour setting everything up & began spraying. I've never used it before, so I needed everything ready. Got about 1/2 way of just the backing to the batting & the can won't spray anymore! It's still full. I ran the top under hot water, air flows through fine, put it back on but nothing comes out when depressed. What do I do now? Store won't open for another 4 hours... Any suggestions would help!