Help with Eames shell chair glides.  

You can't. You have t drill...
You can't. You have t drill them and push them into the leg tube and replace with new ones. Trust me on this one.

Pliers
I used pliers and gently worked it out of the leg tube. I was successful on one leg of one chair out of about 15 with this method. Most of the others either mashed up the glide or broke it completely.

A Solution That Works.
Remove the base from the chair. Get two hammers and a pair of pliers. If there are remnants of the bottom piece, or even a full bottom piece on the leg, use the pliers to turn it. Sometimes the glide will come off by doing this, otherwise just continue to twist until it breaks off. Inside the remainder of the glide is a pin (like the head of a nail) that slides in and out. Secure the pry fork of one of the hammers around it, put your foot on the base so it doesn't jump around, then strike the hammer with another hammer. A couple of good shots and the entire glide will be removed.

Wear safety glasses.
Striking one hammer with another is dangerous.

I grip the edge of the glide...
I grip the edge of the glide VERY hard with some pliers, gradually work it off slightly - even just a few millimetres, then get a small flat head screw driver in the gap and push. Recently moved 4 this way. Don't break the end off etc as it only makes your job harder.

Sheet Metal Shears
I just removed 5 w/o a hitch and not much damage with sheet metal shears. Worked the blades between the plastic and the bottom of the pipes. Then rocked the shears back and forth, moving the blade up as more plastic was exposed. Minimal damage to the glides. Put one in a chair that was missing one right a way. No prob.