We've been accused of a lot of things, not the least of which is featuring Eames shell chairs too frequently. We've also been accused of giving the wrong advice for how to restore them to a glowing shine. Well we still love them so we won't offer a moratorium on talking about them, but we can offer the best tip we've heard for how to (really) restore a fiberglass shell chair yourself. We stumbled upon the advice through Land+Living who linked to Chair Fag's detailed step by step for how to restore an old shell chair. And although they go into detail about removing and replacing the mounts for the legs, what we were most interested in is how to restore the glossy shine to the fiberglass (we've resorted to olive oil in the past).
It turns out it's a product called Penetrol, an oil paint conditioner that you can find at most home improvement stores. (They do warn not to use it on white shell chairs as it yellows slightly over time). You'll want to read the step by step, but the penetrol seems to add back lustre to old fiberglass. See how to apply it on Chair Fag. Image from The Good Mod.