You heard from a friend in the business once that shapeshifters hate acid. Throwing on one while it is in a guise will force its skin to bubble and melt away, leaving the true creature underneath until it tries to take on another form. Throwing acid on one mid-transformation might well kill it outright. At least thats what you heard.
Acid will not kill a shapeshifter, but will force its skin to melt off, it will also prevent it from taking a new form for 24 hours during which time it will be in agonizing pain any time it tries.
Shapeshifters can only be killed by silver weaponry.
Reveal shapeshifters by shining a light in their eyes and look for some telltale reaction?
Shining an unnatural light source (of bright illumination, not dim) on a shapeshifters eyes will cause them to glow red.
Pure iron, the kind found in cold iron blades or most higher end tools (but not steel) is said to be effective at forcing some kinds of spectres to disperse for a time, however it leaves them mad.
Fact: Iron will cause a ghost to disperse, only if it is cold iron or iron smithed for tools as opposed to the treated iron in weapons and Armour.
Supposedly, salt can drive off incorporeal undead when tossed on them.
This is true, also incorporeal undead in general cannot cross lines of salt, so putting irt around a doorway will stop a ghost from passing through it and putting salt in a circle will prevent a ghost from entering or exiting it. Ghosts can not teleport inside or outside of salt rings either.
Apparently truely angry ghosts leave residue.
Angry ghosts are powerful ghosts, ghosts that are incredibly angry leave a black tar like substance where they have been called ectoplasm. Finding ectoplasm at the scene of a haunting means you are dealing with a very angry and very powerfukl ghost.
Ghosts are generally dealt with by burning all of the remains of the ghosts body by slating the bones then burning them.
You once heard a hunter speaking, saying that witches are always disgusting, the rituals they perform often involve living or once living components.
Witch rituals often involve organs, bones and blood. Be that of the witch them self, a victim or a beneficiary.
Fire is very effective against trolls, according to the grizzled hunter who was boasting in the bar, he didn't say how however.
Fire is something trolls fear, wounds that are caused by fire or have fire introduced to them will not regenerate like a normal wound for a troll, and will instead be forced to heal at a normal mortal rate.
Most demons can only exist on this plane by possessing sombody.
Should they get possessed their eyes will turn black normally, with more powerful demons turning different colours.