Here's a tip passed to me through several players.
When mining clay and crafting urns, take a stack of the appropriate rune for whatever type urn you're planning to make, and add the runes right there in the crafting guild to stack your urns and save yourself a banking trip. It will use two dedicated inventory spots - one for your runes, and one for your runed urns - and you'll just make 13 urns at a time instead of 14.