A Skein Bowl is a ceremonial tool that commonly takes the form of a metal or wooden bowl. The bowl is popular with the priests of Wintermark, where it is also sometimes called a Scop's Well or a Stormcrow's Basin. As part of a ceremony of testimony, the priest mixes a dose of liao with a little water, oil, or even blood (the latter is especially popular with the Navarr). During the testimony, the resultant mixture is used to either physically mark the body of the ceremony or flicked towards them in cases where they are not a willing participant.

In Highguard and the League, this item is called a Righteous Aspergil and takes the form of a perforated sphere on the end of a short rod. The liao is mixed and poured into the sphere, which is used to flick the resulting liquid over the target in fine droplets. In Urizen, the item more commonly is called a Spiritwell and the liao is mixed with a little ink that is used to carefully trace a sigil on the hand or face of the target of the testimony - these items have seen increasing popularity in the Brass Coast where the liao is often mixed with henna and used to trace beautiful intricate designs on the target. This has replaced a more robust version of the item, still favoured by some sutannir, called a Glass Bowl in which liao is mixed with a little spirit that is imbibed by the priest and then sprayed toward the target at the climax of the ritual.

Regardless of the exact shape it takes, it is used in religious ceremonies and directly empowers the ability of priests to mark a target's soul. It is a tool that can be used both to create indelible marks - marks which are much more durable than normal, especially where the testimony is part of a punishment or warning - but it can also be used to empower a priest to remove such durable marks.