This trick is for Hot and cold (Hot and Cold - Quest - World of Warcraft)
Basicly you have to grind 5 essence of ice from the Brittle Revenants (Brittle Revenant - NPC - World of Warcraft) and then cool off 5 Iron scraps (found around 77,62). Basicly the trick i do is grind the brittle revenants untill i got around 50 essences of ice (They also drop eternal earth and ulduar relic wich will become very valueable in 3.0.8 since they will be no longer BOP and will be used as a turn in for SoH rep). Then i put 45 in bank (very important or you'll lose them once you delive the quest). Then i deliver the quest and the next 9 days i can do the daily in just a few minutes since i already have the ice.
So basicly:
1. Grind essences of ice for multiple days
2. Put those you dont need in bank
3. Turn the quest in
4. The next day you can complete the quest very fast
What's the exploit?
Normally you're supposed to lose the quest items