If one of the salts forming is insoluble, it will precipitate. You just have to filter it off and evaporate water to get NaCl.
For example, reactions in water:
* 2NaI + PbCl2
2NaCl + PbI2
has a low solubility in water. So you filter it out and you're left with salty water (and still some traces of Pb2
2NaCl + BiSO4
(oxalate) + CaCl2
2NaCl + Ca(oxalate)
Calcium oxalate is damn insoluble in water.
If you don't want to use water, you can use sodium metal or hydride:
This reaction is between a solid and a gas, so it will react only at the sodium surface.
* NaH + HCl
NaCl + H2
Hydrogen is a gas that just flies away
NaCl + HCONH2
You could use an acyl chloride and sodium amide.
There are many many other ways. But the easiest way is to go buy it. No bother making it