Actually, what some of us do in the dirt bike world is use double sided ele. tape. Wrap the area of the bar or throttle tube that will receive the grip and just before sliding it on spray the tape with carb cleaner. Slide the grip over the tape while it is slick form the spray. You may even be able to use hair spray but personally never tried it on tape.I don't know it it applies in your case but if you have a loose fitting grip you can solve the problem by putting a very thin, barely overlapped wrap of electrical tape on the grip first. Then spray the inside of the grip with WD40 and slip it on. It has to then sit for 24 hours undisturbed and it should never move again.
For normal grips I've always used hairspray also.
I'm surprised so many of you have hair spray in your toolbox. Have you ever tried using your lip gloss?:green_lol: