Signs of Infestation
In general, most mole species prefer moist, sandy loam soils. Moles always build networks of underground tunnels, so the most obvious sign of a mole problem is small mounds of dug up soil. You may also notice larger mounds of soil called molehills where the mole has dug a nest cavity or a deeper tunnel. Occasionally, you may notice the mole itself burrowing or traveling across the lawn, but this is rare as moles typically avoid human contact whenever possible.
Household Control Methods
There are numerous household methods for controlling a mole problem in your lawn. Moles only take up residence in a lawn if there is an abundant food supply in the lawn, so the first and one of the most effective control methods is to eliminate the food source, usually grub worms and earthworms. A more drastic measure is to install a mole barrier, essentially an underground fence that cuts off tunnel digging routes moles use. But this can be expensive if trying to remove moles from an entire yard. There are other, more colloquial mole control methods like pickle juice, broken glass, red pepper, razor blades, bleach, moth balls, rose branches, human hair balls, vibrators, ultrasonic devices and Castor Oil. But experts doubt the effectiveness of many of these approaches, according to Ohio State University Extension.
Other Control Methods
If natural control methods do not effectively remove your mole problem, chemical controls can be a last resort. Commercially available poisons are marketed as mole control methods, but because the poisons are typically delivered via peanuts or grains rather than through the mole's natural food source, poisons are probably only effective in driving the moles down to deeper tunnels in search of a food source. Small gas cartridges sold at hardware stores can also be placed inside mole tunnels and sealed with sod for the purpose of fumigating the tunnels -- but again, this method most likely only drives the mole down deeper into the yard rather than getting rid of them altogether.
Natural control methods are always preferred by experts over the use of synthetic chemical solutions, since chemical solutions can very often harm beneficial animals and insects and since using chemical controls always presents health and environmental hazards to the are in which they are being used. But in the case of moles, household control methods are actually more effective at removing moles from your lawn than are chemical methods.