compressed air is probably the best way of getting grips on and off the bars, but i dont have an airline, so for me the best way is useing hairspray.
using a small flat head screwdriver, try and force a gap between the bars and grips, then spray hairspray into the grips. this worked for me taking the grips off, but i couldnt use the hairspray trick to fix the grips onto my new bars, so i took it to my bike shop and they used their airline to put the grips on (Y)