[generalbrando]

I've done exactly that before and I know how you can do it. Great Stuff. There's this expanding insullation in a can called Great Stuff. It's hard to use (don't get it on skin!) but if you dip an egg in vasoline and then surround it with this stuff (use a little box or something) then you can cut into it and take the egg in and out. Then just use a couple tight rubber bands to hold it together (if you cut in squigles or something, it's less likely to come apart!).

Hope this helps.