I won't speak to the purification aspect (though I suspect purification is quite trivial), but helium released into the atmosphere is wasted. Saying it's not destroyed is by the by, we aren't going to recover it from space as it rapidly escapes the atmosphere.

https://en.wikipedia.org/wiki/Helium

It's to hawk, to sell out in the open as a hawker would. https://en.wikipedia.org/wiki/Hawker_%28trade%29?wprov=sfla1