Refining Tin (Sn)

I am a Copper Cookware Tinner & have a problem in reusing much of the tin that I end up sweeping off the floor etc. Prob about 5kg over the year & it would be great to save this?


Now, my workshop will definitely have copper dust around the place & possibly other metals?


What is happening when I re melt all the sweepings is that I am getting a casting of tin that is not quite all tin I believe? Instead of nice flat crystalline structure, I am getting long needle like crystals. This I am told is due to some copper being percent in the finished metal? I have heard this can be cleaned/removed using sulfur?


As you can probably tell from the terms I am using, I am no scientist, but I would be very grateful in learning the practical aspects of getting this tin back to near 999 grade as I originally receive it


