This Mote of Fire farming guide will show you the places that I use for farming Mote of Fire. There were no major changes to Mote drop rates at Outland, so this guide can be used for Burning Crusade Classic (TBC) and Retail WoW.
Primal Fire comes from combining 10 Mote of Fire, so if you need Primal Fire, you have to farm Mote of Fire.
Mote of Fire
Killing Incandescent Fel Sparks in Hellfire Peninsula at Throne of Kil'jaeden is the best way to farm Mote of Fire. The respawn rate is fast enough that you will never run out of them.
Watch out for the Felblood Initiate mobs, they are unkillable and will always stay on 1 HP.
Nagrand is also a good place to farm Mote of Fire, but the respawn rate of the Raging Fire-Souls is not as fast as the mobs in Hellfire, so you will have to wait for respawns if you kill them too fast, or if you have a lot of competition.
Enraged Fire Spirits have a lower drop rate than the previous two mobs, and they only drop 1 Mote of Fire most of the time. But, this place can be used as an alternative if everything else is farmed by someone else.
Blade's Edge Mountains
Searing Elementals also drop Mote of Fire, but the drop rate is not as good as any of the previous places.