Damn cat ran across my lap while I was having lazy TV supper. Tricolore salad, lovingly prepared by dh seconds earlier, went everywhere. Left nasty stain on rather nice chair that my mother re-covered for me. Need help before she visits!
Alternatively: For sale - one rather lovely chair. Seat cover slightly soiled.
I always rub some washing up liquid on olive oil stains on clothes , then put them in machine on normal wash - works a treat. So if they are washable covers try that. Otherwise I would rub the stain with a bit of washing up liquid on a cloth and then use a topical unholstery cleaner afterwards.