Brass is highly resistant to atmospheric corrosion. There is a reason it was widely used on ships before stainless steel came along.

I've loaded and shot plenty of black tarnished brass I've found in the field I shoot at, with no adverse effects. The reason being pretty much the only way to "hurt" brass is by work hardening, i.e. shooting and resizing, not corrosion or tarnishing.

Load it and don't look back.

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an actual conservative