Taint comes in three different flavors, Wyld, Weaver, and Wyrm, and is represented by a permanent trait on the character sheet. Taint is gained in a few ways. It can be gained by spending time in areas heavily influenced by said Triadic force. It can also be gained by engaging in activities that promote that force. Needless killing and destruction for example can cause you to become tainted. The Storytellers decide what warrants a level of taint. Also, mechanics will be employed depending on the level of taint a character might be at. These will be reflected on the character sheet. They are not shown here for the fact that some levels will indeed give bonuses to certain things while giving drawbacks to other things. Certain events and or actions can warrant gaining more than one level of taint, but should not happen often. Certain situations and Umbral Realms can give taint just for being in them.

Minor Taint

Minor Taint is the most common. It is rather easily cleansed. This would include taint gained from taking a drive in the city and doing routine missions and the like. Generally speaking this is the taint you get rid of before entering a Caern from a mission. This is not to say those missions cannot deliver permanent taint.

Removing Minor Taint

The first three levels of minor taint can be removed easily with Rites of Cleansing and the like (often done on game floor).  At higher levels, it may take major downtime actions and another character to aid the person who is tainted.  If cleansing is not done fully then a chance exists that the taint will increase in stacks of Minor taint or upgrade to Permanent taint. 

Permanent Taint

Any character may gain up to Five Points of permanent Taint of each type. As soon as the character reaches five points of any individual type, they become Unplayable and are immediately transferred to NPC Status. At level 3 taint the corresponding taint will actually start to talk to you and encourage you further down the path. To actively avoid this the character will need to spend Willpower when tempted. This can also happen in downtimes if said character is not being cleansed. In which case unless the player chooses not to (the Staff will be sure to talk to the player) they will start next session down a willpower point, lowering the biddable Willpower they have. 

Removing Permanent Taint

This requires more effort than a simple ritual in most cases. It should be expected that a scene is required to remove Permanent Taints. A suggested table of downtimes that can be used in lieu of a scene, with ST guidance: