What's the opposite of oil? Hmm.
Demeter's Tears
Perdo Ignem 10 (Base 4, R: Touch, D: Diameter, T: Single) charged item
A small vellum pouch of marble dust, with glittering mica and white gypsum powder stirred in. By throwing a handful of dust while shouting "Keep out!", the person or beast the dust coats will be filled with a dire chill for one diameter. This cold is enough to remove a Fatigue level for each turn of exposure. If the target does not seek sanctuary immediately, they are likely to fall unconscious from exposure. Common sigils for this item will cause the dust to cling long after the effect ends, or leave the affected person's skin ashen for the rest of the day. The lab text for this item includes the +3 bonus marble gives to cold and chills.
A common tool used by the Colombae of House Ex Miscellanea. Though they may specialize in wards and boundaries, and they may suffer a reputation as "pigeons" among other magi, Colombae who wish you to keep out of their space have more than one method of making you remain outside their space.
Threatening Meridian Sands
Creo Imaginem 15 (Base 2, R: Touch, D: Diameter, T: Group, +1 complex animation) charged item
A collection of linen pouches with wax seals, containing powdered cinnamon mixed with crushed rose petals and red cinquefoil dye. Scattering a pouch of powder on the floor while speaking the phrase "covered in scorpions" causes dozens of images of tiny black scorpions to appear in the affected area for one diameter. These images create a persistent clicking and skittering sound as they swarm and rush over each other. Because the images cannot react to or interact with anything, they are only useful as a deterrent to intruders who are already cautious. The lab text for this item includes a +3 bonus to Imaginem from the cinnamon. A person familiar with Magic Lore or Magic Theory is likely to recognize the Threatening Meridian Sands as an illusion if they smell cinnamon...
Another Colombae creation, less famous than its imitators elsewhere in the Order of Hermes. One popular variant is a Creo Mentem formula which merely convinces a target they are covered in scorpions.