For matches, I wet tumble all my brass rifle and pistol. Does it need to be, "no". Wet tumbling with stainless steel pins is great, you can take the dirtiest old brass and when done it looks like new. However, after reloading for over 35 years, I don't think it makes a difference other than appearance. The one thing that is really great about wet tumbling is no dust, walnut dust and my allergies never got along well.