When you want to remove some handlebar grips force a sharp object - a small screwdriver for example - between the bar and the inside of the grip. A shot of "that magic potion in a 12 ounce can" acts as a solvent for any glue and helps the grip slip off sweetly.
When you want to refit the grips the spray helps them slides on then dries for a permanent hold. It makes the place smell nice too.
all together now....
"Go Ricki. Go Ricki. Go Ricki. Go Ricki. Go Ricki....."