Warning: Compressed air is dangerous. You are responsible for your own safety. Fire extinguishers can cause massive damage if activated indoors.
Canned air is nice for blowing clean PCs and other things for dust, but the cost of those disposable cans quickly add up.
A fire extinguisher should be replaced or have an expensive service after 10 years. Service and refilling costs the same as a new one, so what to do with the old one? The short boring answer is to deliver it as special waste at the nearest depot, but are there better alternatives?
The tank of a standard fire extinguisher is usually rated at 15 bar. How about a handy compressed air tank for the small jobs where the compressor is cumbersome to carry around? Converting a fire extinguisher to a portable compressed air tank is easy and straightforward.