How do you "un-Iray" something?

If a product is optimized for Iray only, is there a quick and easy way to remove all the Iray presets so you can apply your own, preferred 3delight shaders and textures? 

I see many Iray-only props and environments on sale in the store right now, like those by Polish for instance, only I'm really interested in the geometries themselves, not in achieving the overall Iray "look."