+1 hairspray, if you're quick it slides on easy and after it sets it doesn't slip, in my experience. I'd use this instead of glue if you don't have compressed air. So you don't have to resort to a razor to get them off.
Compressed air makes it easy to take off and put on. I haven't had to yet on bicycle grips, but on my moto bike I had to drill a hole in the end a bit smaller than my air chuck and start the grip as far as I could slide it and finally give it a blast of air and the whole thing balloons up and slides on easy. The other end of the bars has to be plugged by something or someone.
Taking the grips off you can just peel up a bit from the inside and slide your nozzle in there and walk it off with a little twisting and pulling as someone said. I didn't have to use anything to loosen it up, couldn't hurt.