No need to clean them up. I use a section of an old propane tank, and melt down a couple hundred pounds at a time. When the wheel weights melt, the manure comes to the top, where it can be easily skimmed off. Then use some flux to stir around in the mix, to further clean it. You can use any carbon based material for flux. Old motor oil, saw dust, candle stubs, anything as long as they are dry. If there is moisture in anything that gets below the surface of the melt, it will create a steam explosion. I've cleaned up a couple tons this past year doing it this way. I shoot a lot of pistol, BPCR, and bottle neck rounds during the year, and go through a considerable amount.
I like WW's for round balls, as I do like the deeper penetration on elk and such large critters. And the people who I beat in competitions, when it happens, don't seem to cuss much more than if I was using pure lead.