Ok everyone - how about getting rid of moles?

My boss has had them in his yard for over a year. They dig tunnels under the grass which makes it spongy and unattractive. He doesn't use all the chemicals and poisons in his yard that all the neighbors use so not only is his yard pretty poison free, but it is filled with tasty grubs and worms (which are good for the lawn and plants).

We've tried a professional setting traps but the traps almost never work, and it's costing a lot of money considering the effectiveness. I found that castor oil is use to spray on the lawn because universities have tested that moles don't like the flavor of it and if you soak the lawn with it, the worms get coated with the oil and the moles will supposedly move away to find better tasting worms. We've tried it over the past few months and it isn't working.

Any ideas? Personally I could care less because I'm pretty much anti-lawn, but he's my boss and it would be good to have an actual solution to this issue.

Thanks!

Blackcatter