How can I wash leather couch cushion covers that smell like smoke?

I just bought a leather couch off of craigslist with removable cushions. The couch smells like smoke, and I'm not sure what else has been on it, so I want to clean it well. Can I just take the cushion covers off and throw them in the wash? Do I need a certain cleaner? Or to put the wash load on 'delicate'?