For failure isolation, energize the suspect PC board. Spray on board to determine the area where the failure is occurring. Attach extension tube and spray on individual components until the failed component has been isolated.
It may be different state-by-state, so contact your state environmental agency for regional specific regulations. For a general guideline, here is the process according to EPA hazardous waste regulations 40CFR. The can has to be brought to or approach atmospheric pressure to render the can empty. Puncturing is not required, only that it “approach atmospheric pressure”, i.e. empty the can contents until it’s no longer pressurized. This insures that as much contents as is reasonably possible are out of the can. It is then considered “RCRA-empty”. At that point it can be handled as any other waste metal container, generally as scrap metal under the recycling rules. Note that the can is still considered a solid waste at this point (not necessarily hazardous waste).
The aerosol trigger sprayers that are common on dusters, freeze sprays, and flux removers, have two ways to store the straw when not in use. The hole at the back of the body of the sprayer is just the right size for the straw to slide into place for storage. The slot below the trigger is also the right size for the straw to snap into place, which also has the advantage of locking the trigger.