If the corrosion has migrated to the fixed contacts in the radio, they must be repaired or replaced. Otherwise you will have an intermittent connection. I just went through that with my 7UAFS. If you send your radio in to a shop, they will fix that too. Be sure to mention it in an accompanying letter.
If the corrosion/leakage has gotten to the circuit board then the condition could be much worse.
Long term storage - remove the battery pack. Long term = more than a month without use/examination.