Handlebar grips

[5th_bike]

Nonsense. The air will just fly through the hole in the rubber. All you will get is noise. I also would not want to put oil there, for fear of losing my handlebar weights on the highway at any point in the near future.

Do what alantf said, use a coat hanger or something else with a hook, like a bicycle spoke, to pull the rubber out. If you happen to damage the rubber to uselessness, order a new one.

When you put the new/restored one in, make sure the nut is snug enough to be able to tighten the bolt to make the rubber expand.