Sometimes when I attempt to have a Temple Healer uncurse an object, they take the gold, close their eyes and nothing happens!
Do I need to be wearing the cursed Item?
Do I need to be visible?
And I'm not speaking of some uncursable thing, or high level object.
Just a talisman, for example.
Any thoughts?
It might be a noremove curse.
You can't do, heal uncurse talis. It has never worked. I have no idea why not, but after years of playing it never has worked. Just do: heal uncurse talisman.
its happened to me a few times even when I spell it out, make sure if you have two and one is allready uncursed that you place it in a sack before you get the other, then try it. I have a few times done this forgetting.
Its happened for me even when I spell it out. I just figured even though they were uber-high level they still failed sometimes or something.
Demon-talismans? Come on guys...."Demon" Makes yah think right? 
If you're non-evil, don't waste your money: Ask help from someone who can uncurse.
Try uncursing the High Guardians' facemask. 
Sometimes when I attempt to have a Temple Healer uncurse an object, they take the gold, close their eyes and nothing happens!
Do I need to be wearing the cursed Item?
Do I need to be visible?
And I'm not speaking of some uncursable thing, or high level object.
Just a talisman, for example.
Any thoughts?
Also, make sure you aren't WEARING anything else that matches what you are typing in for the healer to uncurse.
Plain and simple, healers will fail from time to time.
Another thing to note, mobs don't have autoaim, for those of you trying to uncurse talis rather than talisman.
