The Sparklematic 5200!
Insert a Grime-Encrusted Item into the Sparklematic 5200, and be sure to have three silver coins to start the machine.
Description
This contraption stands out amongst the gnomes holding out against the madness outside the room. A small plaque on the device reads "The Sparklematic 5200", followed by some text:
"Grime and residue ruining your sparklies? The Sparklematic 5200 puts the shine back in shine-tastic! Insert the item you wish to clean and deposit three silver coins in the coin slot. Give the Sparklematic 5200 a moment for operation, and voila! Your valuables will emerge clean and shiny!"
To complete the Grime-Encrusted Ring quest -- the objectives will not show up on your dungeon map -- place the Grime-Encrusted Ring into the The Sparklematic 5200 found inside The Clean Zone within the Gnomeregan instance. I found that only one of the three Sparklematic machines allowed me to insert the ring, so if the first one doesn't work, try the others.
Turning it in rewards a Brilliant Gold Ring . You will also receive the quest Return of the Ring to return the ring to an NPC in Ironforge or Orgimmar, depending on your faction. Bring the NPC some additional materials and he will upgrade the ring to Nogg's Gold Ring.