to get grips off if I intend to re-use them, I slide a barbeque skewer under the grip then insert the red tube and squirt WD inside and wiggle till they free off then use fairy liquid to wash that out and after a good rinse and dry they're ready to go back on.
Thats perhaps the best way of removing grips, but now i just use an old 22mm open ended spanner and a hammer a quick tap or three and they are off very quickly.