Alternatively you could take them along to your local co-operative owned olive pressing facility and extract the oil from them. I believe that is what they do in Italy and Spain.
I once saw a TV prog about "proper" food vs the equivalent made by vast conglomerates. Olives was one example they used. The large company in Spain used something horrible like peroxide to soak them in for several weeks to make them edible, the small farm in South Africa soaked them for months and months in brine (I think) the best bit was when the reporter asker the farmer if he could pick one to try. The farmer turned to a group of women who were picking nearby and announced "ladies: this gentlemen wishes to try one of our olives!" the women collapsed in giggles; The reporter picked an olive, put it in his mouth and immediately spat it out in disgust.