After a couple of months of not resizing bullets I decided to do some sizing and reloasding. I had some bullets that was put away in a airtight ammo can for a couple of months and in it, it had a tray that was sized a couple months ago that was stored on the tray with the rest of the bullets that were not sized. The ones that weren't sized were bright and shiny. However, the ones that were sized with Lyman Moly had these powdery substance all over them. The two batches of bullets were made from the same alloy.
Can anyone out there let me know what is it or what is happening here?