Dies scratching the **** out of brass!

My RCBS 357 resizing die is scratching my brass. I have resized 200 357 NICKLE cases with the die, and that's when the problem started. The inside of the die looks smooth as silk, but evidently it ain't! How can I polish the scratches out? I thought about using 0000 steel wool wrapped around something in my drill to try to polish it out. Or just buy carbide sizing dies and start over. Any advice appreciated.

Ive never heard of this, but maybe some sort of grit got in your sizing lube if the dies arent carbide. I always use carbide dies.

all my pistol dies are carbide and ive never had this problem..
Carbide is hard, so give the steel wool a try and see if it helps.

Same thing happened to me with a set of 44mag dies. The sizer die leaves very noticible scratch mards up and down he case. I tried some polishing compounds but without success ... a new carbide sizer die cured the problem .. This was an old, old set of Lyman dies ..

die lapping 101... Find ridgid object slightly smaller than opening in die. Dowel rods work nice. Get 1000-2000grit wet sandpaper. Cut a two inch wide strip the length of the paper. Tape one end to the rod and and wrap the rest around the rod. Soak in water for a few min. More than likely it will no longer fit inside the die. Remove a half turn of sand paper at a time untill a good fit is found. Attach high speed drill to the other end of the rod. Run it in and out a few times wash it out then look for any burs as they should be very shinny. Repeat untill slick. Remember to always keep die and paper wet

Thanks, I'll give it a try.