I found 4 Eames shell chairs on Ebay for $200, needless to say for that price they were in pretty rough shape. After reading a few restoration tutorials (The Brick House, Chairfag) I felt pretty confident they were worth it and could end up looking pretty dreamy.
Luckily most of the shock mounts were intact, I only had to order one other set from Modern Conscience along with 4 Walnut Black Dowel Bases and 4 sets of coarse thread screws to attach the bases to the shock mounts. I guess the chairs used to live in an elementary school because there was petrified gum under all of the seats.
Most of the seats had some pretty bad chips in the fiberglass along the edges. The dark lines are just dirt ground into the fiberglass where some fibers had worn away. I sprayed down all the seats with oxyclean and let them sit for about a half hour then scrubbed them down with a coarse sponge. Then I wet sanded each seat, first with medium grit then fine grit sandpaper. Make sure to keep the seats wet using a spray bottle of dish soap and water. I would absolutely wear a pair of gloves during this part, things get pretty itchy.
Here are the chairs after cleaning and sanding
The cracks on the side are a little less visible, but since they make the seats weak I decided to fill them with some white marine epoxy. You can find it at most hardware stores just make sure its the right color and works on fiberglass. I let it sit for a day then sanded it down. Then I rubbed the seats down with a few layers of Penetrol, which will condition the fiberglass and make the seats perfect and shiny. I read some places that Penetrol can yellow over time but since my chairs aren't bright white I wasn't too concerned.
Here's a closeup of the deeper cracks filled with epoxy on a freshly Penetrol'd chair.
Then I put together the bases and attached each to the shock mounts.And voila! 4 pretty near perfect Eames Shell chairs! I can't wait to get another to use at my desk and a rocker armchair for the living room.