Am I doing something wrong with the propane can?
Answers:
Some decompression of gas remains normally for a few minutes but should stop. If it just keeps going, check the seal on the canister seat carefully.
Don't use propane canister stoves indoors, in campers, or tents. Good luck
Other answers:
you got a bad propane tank
you got a bad propane tank
You could reattach it to the Grill and use the On/Off knob on the Grill. Sometimes they do leak as they not seal when removed. Then you lose all your propane.
Try stabbing it with something really sharp ^_^ If that doesn't work, heat it to about 250ยบ F, you will really see a difference after that lol...
P.S. As a security precaution for stupid people, I want to say that doing either of these things will cause the canister to explode, and you will most likely die. So, don't try it...
DO NOT LOOK FOR THE LEAK WITH A MATCH IN THE DARK ! use soap and water to find the leak, sponge on the solution, look for the bubble, use a flashlight !