Funfest missions!
No, seriously, you can do them solo. There's one specifically called "Find Shards". It takes three minutes and I usually find between 15 and 20 shards. Of course, not all of them are going to be blue. But it's a hell of a lot more efficient and reasonable than dust clouds OR losing the PWT. If you also want some Evolution Stones thrown in the mix, you can do "Find Mysterious/Shining Ores", depending on your version. Blue shards show up in Black 2 version's "Exciting Trading!!" along with Max Revives.
Seriously, guys, do not underestimate the usefulness of Funfest Missions, even solo. Doing them is a reward unto itself. The fact that you get Pass Orbs to do shit like get increased Audino chances is just the cherry on top.
