Placing Nasty Substances in Mole Runs

Effectiveness
Ease of Use
Durability
Overall Rating
 
There are two options here; organic or chemical.

On the natural side, many a blogger and mole control theorist will advocate the virtues of peeing on mole hills. This, together with a variety of related techniques such as burying mouldy vegetables, peppermints, used cat-litter, chili sauce, rotting fish, powdered aspirin, onions, or garlic.

On the less environmentally friendly side, options are: petrol, diesel, engine oil, bleach, creosote, chewing gum, and the least damaging: (but equally useless) mothballs. This is quite simply a bad idea. Not only will it not work, it is likely to cause widespread contamination of watercourses and will cause more permanent damage to your lawn than a mole could do in years.

Whilst free, or at the least very inexpensive, these methods are a waste of time. Moles will simply either ignore these substances, or tunnel around them. The only benefit may be extra fertiliser for your lawn if you use the natural substances!
Verdict
Definitely don’t bother!
unpleasant mole deterrent