Does Dug Scrap Copper and Brass....

have to be completely free of dirt before the scrap yard will take it? I was also wondering if deep cleaning with acid (sulfuric) would take dug copper into a higher grade as Sulfuric really gets copper bright looking.

Any thoughts on this welcome.

Cheers
Alan in NH, USA

I don't think dirt would make the scrap yard not take scrap metal, but just washing most of the dirt off would be a good idea. As far as using acid to clean up things to get a higher grade, I'm guessing you are talking about copper wire. It will shine it up, but some acids and cleaners like CLR for example will make copper shiny at first, but it will usually turn black after a few days or a week, so scrap it soon after if you clean it.
You might want to check out the cleaning coins area on these boards for more about cleaning metals, like copper cents, they are basically the same as wire or copper pipe.

May want to check to see if your scrap yard even pays more for shiny wire.  Some places do some don't they will have a #1 and #2 price and then pricee for sheet copper or something.

Why mess with the hassle of acid? If you have a tumbler or cement mixer, chuck it in with a couple pinches of baking soda (79 cents or less) tumble till clean. baking soda is easier and safer to get rid of than acid also. No mixer or tumbler? 5 gal bucket spin back & forth by the handle rinse & dump.