I have crumbled a bunch of dried oak leaves and used those; they worked fine.I have a bunch of pine needles in this latest batch, hope it's as good of Flux as saw dust....
Sawdust mixed with used motor oil is a favorite flux of mine as well.I have crumbled a bunch of dried oak leaves and used those; they worked fine.
Really, anything to get carbon into the melt. I've taken to pouring a few ounces of used motor oil in the dirty melt. It works very well, but one must be careful about how much is used.
I use sawdust with used motor oil mixed in also.
Your collecting on the opposite side of the range this is about lead.Please excuse me, but this sounds like the old cowboy joke that asks what do they wear underneath "Huggies" or "Always". The answer is "Depends".
I may have mis understood your questions, so I will answer both ways. I do not wash scrap. It goes to the junk yard as is, less any live rounds or primers. Range brass or even picking up my own for reloading do get a lot of dirt, sand, and pine needles and .22 cases stuck inside and are mixed in and so I do hose them off once in a while. I let them dry off real good before tumbling them with walnut.