I clean range lead/bullets by dumping them in a metal strainer and spraying with hot water while agitating vigorously. With a little motion from me, the bullets clean each other.
I allow a minimum of 3 weeks drying time, but often go many months (4-8) before they're melted down.
I'm still searching for the 'perfect' flux, but I'm using paraffin and cedar/hardwood chips/dust at the moment. (Don't breath the cedar smoke.
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The hardwood and cedar sawdust/chips are the real flux, with the paraffin added after all of the wood is charred.