At the moment, I'm killing lesser demons and imps, in the hope of getting their champion's challenge scrolls. I'm also trying out prayer urns for the first time, and they're pretty useful. Can just bring a few of them along, and the floor is a lot less cluttered. Once they're full, a simple click and it's an easy few k prayer xp!
So, I was thinking about other misc items I never use, and was reminded of a combination I always intended to look into; Bonecrusher + Demon Horn Necklace. 10 prayer points are restored for each normal bone, 20 for big bones, 30 for drag bones. This works even if bonecrusher converts them into prayer xp.
For challenge scrolls this'll be amazing. For example, when killing Goblins I can have turmoil on the whole time, and bonecrusher + necklace will restore prayer faster then I use it. This might also apply to hill giants, not sure.
Guess I'll have to try them both out some time. :)