Originally Posted by
AlphaDogg
Putting them in my car in the sun during this time of the year in my location will put them a little below room temperature.
Also, the grips are cheap $5 ergo-style grips that I really like.
The curing issue doesn't apply to you, between posts, I forgot that you were talking about old grips, which are obviously cured. I think it's strictly a cleanliness issue. Wash both bar and grips well, rinse well with hot water, and consider a final rinse with alcohol. Then dry, and you should be fine with whatever adhesive (or none) you've used in the past.
If you're using hairspray, consider that not all sprays are equal. You want the old fashioned firm hold lacquer type that was used for the "big hair" styles of the 50s and 60s, not the more modern light hold types popular today.