You can take them home...
and wash them. Last year around this time, we had a diesel fuel overflow problem that soaked all the quarter berth cushions. Of course, the foam was a total loss. However, we took the covers home and soaked them for two days in the stationary tub using that orange cleaner you can buy at The Home Depot. Then, after thoroughly rinsing them, we put them through two washing machine cycles using our normal laundry product. They came out better than we had expected. Absolutely no residual fuel odor!