Tasteless Salt

In Matthew 5: 13-16 Jesus talks about salt losing its taste.  How can it do that?  It must take beyond our lifetimes.  This translation must be wrong.  I posit that instead of taste, the word should portray usefulness. 

 You see, in Jesus' time, camel dung was used for fuel.  Salt was mixed into the dung. A slab of salt was placed at the base of the an oven and on top of the slab of salt was placed the dung patty mixed with salt. Salt has catalytic properties causing the dung to burn.  Eventually, however, the salt loses its catalytic properties and becomes useless.