Hi everyone, I have acquired some Perth Mint bullion Kangaroo coins, only a couple of years old. Most of them have got milk spots, is this common for these Australian coins? I thought it was mostly the maples that get the milk spots. Is it storage that causes this? Or is it a manufacturing issue? What about the new ones. Lets say I bought a tube of 2018 x 25 Kangaroo coins, would these automatically get the milk spots too? Any ideas or tips on storage? Any info would be greatly appreciated, thanks.