Rinsing salt

[Zbokowaniec]

Hi. I need some help. I'm building my first boka and I coiled 6 mm copper in two layers. About 7 meters of pipe. I put salt inside and it coiled beautifully and didn't kink. The problem is I can't get the salt out. Is there any helpful solution? I put it into a tank with water hoping it dissolves but to no avail so far. Any suggestions please?