The stable is surrounded by the special "Q" mobs, quest mobs, and has a big door.
For the stable purification quest:
1. go to the sunset witch and take the stable purification quest
2. go to the cathedral in Constantinople and talk to the cleric (Gabriel) outside, he will give you a hat
3. go to the trader (Uvelino) next to the colosseum. Talk with him, he will take his hat. Retalk with him to get a new quest. He will ask for 20 or 30 (don't remember the exact amount) Dow Genetos horns
4. kill enough Dow Genetos to get the horns. These have huge magical attack, they aren't easy to kill and the drop rate is poor.
5. go back to Uvelino, talk to him, hand the horns and you receive holy water in your inventory.
6. go to the stable, kill 20 (not sure of the correct number) Q mobs till the message appears that you have completed that part of the quest.
7. stand close to the stable door, open your inventory, right klick on the holy water. A yellow counter appears in your screen down, in the middle, after running out a message shows up and tells if you were able to gain a filth or if it didn't work.
8. if you run out of holy water before you have your filths, go back to Uvelino, he will give you another 10 holy water without asking for new Genetos horns (hurray)
9. after obtaining your filths, go talk to the sun witch to end the quest.
