Reduce the smell of a cache at its source by washing and drying the container, sealing it with a gasket, double-bagging the food and burying it well down, and treat strong-smelling cover materials as an extra of unproven value. Food smells through plastic, as the parent article says, but I could not find a source showing that pine resin, cedar shavings or garlic hide a cache from a dog.
Part of Hidden Food Caches
Cache scent masking is the attempt to stop dogs, rodents and other animals from finding a food store by its odour, by sealing it or by covering the smell with something stronger.
Eliminating The Trail Beats Covering It
The parent article says food has odour even through plastic, and that animals rely on scent to find food; it suggests rubbing the exterior of the container with strong-smelling natural materials such as pine resin, cedar shavings or crushed garlic, on the theory that eliminating the scent trail eliminates the search cue. Two parts of that deserve to be separated.
The first part is sound: the container’s outside should carry as little food smell as possible. Wiping grease and dust off, using a gasketed lid, sealing food in a liner and putting a layer of soil on top all reduce what escapes.
The second part, covering a smell with a stronger one, is a claim I could not support from this corpus or from anything I could point to. A strong smell may mean that a nose is distracted for a moment, or it may mean an extra, unusual smell at a spot where nothing else smells like it. Search dogs are trained to pick out a target odour among many others, which is general knowledge and not a corpus figure. The fair statement is that masking has not been shown to protect a cache, and that clean sealing is the measure to rely on.
What You Need
- A clean container with a gasket lid and a liner
- Soap or ash and water to wash the exterior, and time to dry it
- A second bag over the container if you intend to bury it without a shell
- Optionally, a cover scent such as resin or cedar, applied lightly and only after everything else
Method: Seal, Clean, Bury, Check
Step 1: Pack so that the food cannot touch the outside. A liner inside, a lid with a gasket, and nothing spilled on the way. Wipe up crumbs and grease.
Step 2: Wash the exterior and let it dry. Handle it with clean hands, not hands that have just cooked.
Step 3: Double-bag and seal. A second bag or a wax coat on the seam stops odour leaving through a lid thread.
Step 4: Bury or place the container so that soil or stone is above it. The more soil above the lid, the longer the path any odour has to travel to the surface. The depth rules in Buried Caches give the cover over the lid.
Step 5: Decide about cover scents. If you use them, apply a little to the exterior after washing, use a plant that grows locally so that it belongs, and understand that it is a gamble. Do not use anything that is food to an animal, since it would draw it.
Step 6: Watch the site. If an animal digs at the spot, the scent got out. Move the cache.
Common Mistakes
- Covering a dirty container with resin. The food smell is still there.
- Using crushed garlic and trusting it. Strong-smelling food scent on the outside can attract animals, and garlic and its relatives are poisonous to dogs, so a dog that digs it up is at risk; see Guard Dog Training.
- Burying the cache beside the compost or a kitchen drain. Those smells draw the very animals you are trying to avoid.
- Putting on so much cover scent that it can be smelled from the path.
Safety
Don't poison or attract the household's own animals
Garlic and onions are toxic to dogs, and any strong-smelling food or resin may attract a dog to dig at the spot. Do not use poisons, baits or anything harmful to deter animals from a cache: the household’s dog, a neighbour’s animal or a child can reach it. Pine resin is flammable; keep it from flame when warming it, and do not use fuel or solvents as scent cover. Buried food is subject to the botulism rule in Waterproofing and Preservation: only dry staples.
What’s Next
- Learn next: Cache Network Planning — how many caches and where
- Combine with: Cache Pest Prevention — rodents also find food by smell