Alfa Sun 5th wheel

Noticed my TV antenna has some cracks around the grey putty around the bracket but didnt noticed any on my other stuff ie., vents and was wondering if I use acetone to clean whats up there can I reseal or do I need to pull the old stuff off. I would like to go around all my brackets and clean and reseal my roof but am pressed for time and am thinking of just doing the antenna bracket. We dont use this antenna so there will be no up and down motion to cause a problem once sealed. Any thoughts from you pros.

Ray